Tanks, of course, debuted in the First World War, and America's delayed entry into that conflict precluded American-built tanks from participating. Gen. Pershing, now commanding the American Expeditionary Force (AEF), first read reports of British and French tank actions in June 1917, and created committees to study the new form of warfare.(4) It took until 10 November 1917 before AEF headquarters ordered then-Captain George S. Patton, Jr., to the AEF schools at Langres to set up a tank training program.(5) Patton and his entourage observed Allied training and manufacturing methods and set about applying the lessons learned. The Army formalized the Tank Service as the Tank Corps on 26 January 1918, and Colonel (later Brigadier General) Samuel D. Rockenbach was assigned to command the unit.(6) Patton was appointed commander of the light tank training school, and later commanded the US 1st Tank Brigade in battle.(7) Manufacturing tanks for the Tank Corps proved problematical due to bureaucratic hurdles, and American tankers fought in European vehicles for the whole of the war. Production of a copy of the French Renault light FT-17 was finally negotiated, leading to the 6-ton tank M1917, but the first of these didn't appear until October 1918, and only 64 were completed by the end of the war.(8) It was also decided to employ a new heavy tank, which was developed into the Mark VIII, and it was intended to manufacture this tank in France using American and British components.
At the time of the Armistice, the US Tank Corps consisted of 1235 officers and 18,977 other ranks, but as a sign of things to come the authorization was rapidly reduced to 300 officers and 5000 enlisted men.(9) The original contracts for 4440 M1917s were cancelled after 952 had been built.(10) The US constructed 100 Mk. VIIIs to its own specifications after the manufacturing coalition decomposed thanks to supply shortages and the Armistice.
The end of World War I meant a drastic culling of the world's armed forces, and the US armored forces were no exception: in July 1919 Congress declared that the Tank Corps would be limited to no more than 154 officers and 2508 other ranks.(11) Despite articles written by Patton and Lt. Col. Dwight D. Eisenhower (who had commanded the stateside tank training center at Camp Colt, near Gettysburg) asserting the Tank Corps should be kept as a separate branch of the Army, the National Defense Act of 1920, passed on 2 June, did away with the Tank Corps and assigned all tanks and their units to the Infantry. This, of course, stifled tank design and doctrinal development, and morale and staffing also suffered. Patton even decided that Cavalry held more of a future than tanks, and joined that branch in September 1920.(12) Nevertheless, the potential of the armored vehicle could not be ignored, and an Experimental Mechanized Force (EMF) was formed by the end of 1927 to test the ability of mobile mechanized units to be self-sufficient.(13) A long-range mechanization plan was created, and Major Adna Chaffee was appointed to head the board overseeing the plan. However, due to the niggardly defense spending policies of the interwar years, the EMF was forced to perform with vehicles such as the M1917 and Cunningham M1 light tanks. Army Chief of Staff Gen. Douglas MacArthur eliminated the EMF as a separate entity in 1931, assigning its remnants to the Cavalry (14), and ordered that all combat branches should modernize themselves as much as possible. Due to this new policy, and the fact that tanks were still technically under control of the Infantry, the tanks used by the Cavalry were forced to undergo a change of nomenclature and were thereafter known as "combat cars."
MacArthur hoped that component development would improve under this policy, and this notion did bear fruit.(15) During the 1930s, the seeds were planted for the components that would make US tanks the most reliable in the world, including vertical volute spring suspension, rubber-bushed tracks, and radial engines. Standardized and accepted tanks were few and far between in the 1930s, and included the Infantry's M2 light tank and the Cavalry's M1 and M2 combat cars, which all used essentially the same hulls. The US also got some medium tanks in 1939 with the arrival of the M2. All of these tanks used vertical volute spring suspensions, which featured twin-wheeled bogies mounted externally. Their rubber-bushed and rubber-shoed track proved very durable on road surfaces, and the curve imparted to the track by the rubber bushings reduced the force necessary to wrench the track around the drive sprocket. Their radial engines were also used to power aircraft, and this would later prove to be a handicap, as engine shortages forced numerous other motors into use. The Lee and Sherman tanks developed for World War II were powered by no less than five different powerplants, ranging from the aircraft-derived Wright and Continental radials and Ford V-8 to automobile motors like GM's truck diesels and the Chrysler A57 multibank, which was comprised of five automobile engines arranged to run as a single unit. The M5 Stuart's development was initiated, in part, to preemptively solve a forecasted shortage of the radial engines used in the M3 Stuart.(16)
There were other American designs during the interwar period, and an enterprising and eccentric automobile engineer named J. Walter Christie was responsible for many of them. Christie had been designing self-propelled artillery mounts since 1916, and incorporated into many of his designs was the ability to move on tracks as normal or on road wheels only. Wheeled movement was usually powered by the use of chains connecting the drive wheels to the rear road wheels. This feature enabled the vehicles to travel at high speeds over roads on their wheels, while also giving them good cross-country mobility once the tracks were installed. Christie's early designs used unsprung or coil spring suspensions, but his M1928 tank introduced his famous suspension design. This individually sprung the road wheels using tall helical springs inside a double-walled hull, allowing the wheels greater vertical movement than the previous bogie suspensions. However, Christie's prototype tanks had a history of shoddy workmanship and unreliability.(17) And Christie himself did not help his cause, as he continually refused to build his vehicles to the contract specifications laid out by the Army, often made modifications to his vehicles unilaterally, and dealt with foreign governments including the USSR and UK without authorization from the United States.(18) The US Army never did wholly buy into the wheel-track conversion theory, but did go so far as to standardize and accept a handful of the Rock Island Arsenal-designed convertible medium tank M1, which used Christie's suspension design. A few combat car prototypes were also constructed along these lines, since Christie's dream of high-speed tanks was more suited to the Cavalry's mobile mission, however none of these vehicles was standardized. The early prototypes of the 76mm gun motor carriage M18 also used Christie's suspension, but this was dropped in favor of torsion bars, which took up less room inside the hull.(19) In the end, the Army concluded that Christie's designs, even those classed as medium tanks, did not provide an appreciable offensive benefit over existing light tanks, while being twice as expensive as contemporary vehicles.(20) While not winning over his home government, Christie did sell some of his M1931 tanks abroad to the Soviet Union and Britain. These countries developed tanks using his suspension, including many of Britain's cruiser tanks and the USSR's BT series and T-34.(21)
The US Marines also busily experimented with armored vehicles between the wars. Armored cars and the little M1917 gave the Marines their first experience with armored vehicles, and weight and size limitations imposed by the Navy's cargo cranes and tank lighters forced the Marines to accept several unsuccessful designs by Marmon-Herrington before it was decided that standardization with the Army would be beneficial.(22) Army M2A4 light tanks were procured starting in 1940 (23), and M3 Stuarts were acquired the next year.(24)
The outbreak of the Second World War forced the United States to reconsider the organization of its fledgling armored units. In Poland, Germany's panzer-divisionen showed the effectiveness of concentrated all-arms formations led by tanks. The US Army leadership, however, was still reluctant to organize its tanks and mechanized forces into all-arms teams, and the Infantry and horse-riding Cavalry each still wanted control over all tank units.(25) But the Army changed its mind thanks to practice maneuvers it performed in 1940 as well as Germany's race through France, and the Armored Force was created on 10 July 1940. To get around the National Defense Act of 1920 and its assignment of tanks to Infantry, the War Department established the Armored Force "[f]or the purposes of service test."(26) The Armored Force, however, was essentially a new branch that combined the separate armored assets of the Cavalry and Infantry, and with its inception the organization of US mechanized forces was finally modernized. However, in March 1942 Army Ground Forces was created to manage ground combat elements, including the Armored Force.(27) Once again, America's armored units were refused independence.
At the start of World War II, the US lagged technologically as well. The most modern US tanks consisted of the M2 medium, and the M2 light tank and its combat car M1 derivative. The medium tank M2 was armed with a 37mm gun and several machine guns, and the M2 lights had thus far been armed with only machine guns. Most European countries, however, had tanks in service that possessed more powerful weapons. In particular, the German Panzerkampfwagen IV was armed with a short 75mm gun, and it was decided that the next generation of US tanks would match the German vehicles in armament.(28) At the time, no turret had been designed in the US that could mount a 75mm gun, so in order to get the weapon to the field as quickly as possible the medium tank M3 mounted its 75mm gun in the right sponson, a setup that had been previously tested on a prototype of the M2 medium. Production commenced as soon as possible to ship tanks, including the British Grant version of the M3, to the British, who were embroiled in the fight for North Africa.(29) Although the M3 was an interim design, it proved a capable vehicle, and its 75mm gun--contrary to British tanks at the time--was able to take care of antitank guns as well as enemy armor. Development of the 75mm gun-turreted M4 Sherman commenced immediately upon the completion of the M3's plans, and the first M4A1 was accepted eight months after the first M3. The M4 was based on the mechanical components of the M3 series, which itself was based on the M2 medium, and the Lee's 75mm gun was retained on the Sherman.
Even though it was not specially designed to fight enemy armor, the Sherman would always be able to handle the opposition's main medium tank, the Pz.Kpfw.IV.(30) The Army did field specialized antitank units, however. The US tank destroyers arose in November 1941 in response to the German "blitzkrieg," and were based on the erroneous assumption that massed towed or self-propelled antitank guns would be able to defeat Germany's tank attacks.(31) The tank destroyers were to hold back if the enemy forces were accompanied by infantry or artillery fires, however, since the basis behind their creation was quite simply the destruction of hostile armor.(32) Unfortunately for the tank destroyers, the Germans were not so kind as to provide massed tank attacks, preferring instead to attack with concentrated combined arms forces.(33) This basic doctrinal flaw would often preclude the tank destroyers from being employed as they were intended, but the error was not realized until the tank destroyers had seen action in Tunisia (34), and tactical doctrine and equipment designs for the tank destroyers forged ahead. The first, and only, purpose-built US tank destroyer was the 76mm GMC M18, which did not appear until July 1943. Before this the tank destroyer forces had used interim designs based on existing vehicles, including the 75mm GMC M3, 37mm GMC M6 (which was nothing more than a 37mm gun mounted on a light truck and was never originally intended to do battle), and the 3" GMC M10. Towed guns were also touted, until it was found just how much more useful the self-propelled tank destroyers actually were.(35) Once the invalid assumptions of the tank destroyer doctrine were realized, the TDs' influence quickly waned: the Tank Destroyer Command was downgraded to the Tank Destroyer Center in August 1942, and the next year Army Ground Forces tried to roll the TDs into the Field Artillery (a move that was resisted by both arms).(36) Further difficulties for the tank destroyers came from the fact that it had been intended from the start to arm the M4 tank with a high-velocity gun.(37) A weapon that was ballistically identical to the 3" gun M7 but light and compact enough to fit in the Sherman's turret had been produced by August 1942, but the Armored Force rejected its setup in the tank as ergonomically unworkable.(38) The 76mm gun turret that had been designed for the prototype medium tank T23 was then satisfactorily used on the Sherman (39), and production of 76mm gun medium tanks began in January 1944, thereby erasing the penetration gap tank destroyers had previously enjoyed. The tank destroyers would reclaim the firepower advantage when the 90mm GMC M36 was introduced, but with the appearance of the M26 Pershing the tanks were again armed just as powerfully as the most fearsome tank destroyer.
American tanks may not have been specialized for tank-versus-tank fighting, but one technological advantage possessed over enemy tanks was gyrostabilized guns on the medium tanks M3 and M4, and light tanks M3, M5, and M24. This innovation allowed the tanks a modicum of fire on the move capability; coaxial machine gun accuracy was improved, and expert crews were doctrinally permitted to fire from moving tanks at ranges of up to 600 yards.(40) German tankers, on the other hand, were instructed to fire from the halt.(41) Of course the stabilizers required proper training for effective use, and rather than try to exploit this feature many units simply disconnected the devices.(42)
Once committed to battle, the M4 had earned a reputation for easily catching fire when hit. Although the crews themselves may have contributed to this risk by stowing extra main gun ammunition (43), work was done to try to correct the tank's flammability. This resulted in wet ammunition stowage being introduced in January 1944, along with other improvements to the medium tank design. Wet ammunition stowage moved main gun ammunition to below the sponson line and stored it in double-walled water-lined boxes. Wet stowage decreased the incidence of fires from 60-80% in knocked-out dry-stowage tanks to 10-15% in tanks with the new arrangement.(44)
American designers had gone immediately to work on an improved tank after the introduction of the Sherman. Effort on this new design, which culminated in the M26 Pershing, commenced in the spring of 1942.(45) However, bureaucratic infighting and the doctrinal decision that US tanks should not seek duels with enemy armor plagued the process. By fall of 1943, the Armored Force was in favor of a vehicle mounting a 90mm gun, but preferred that the Sherman tank be upgunned to this standard rather than field a new vehicle. Ordnance asserted that the medium tank would be overloaded by the 90mm, and instead preferred production of one of the T20 prototype series. Army Ground Forces had no objection to a new tank, and sided with Ordnance on the 90mm gun Sherman issue.(46) Encounters with heavy German tanks like Pz.Kpfw.Panther and Pz.Kpfw.Tiger settled the arguments when the European Theater requested that production of 75mm and 76mm gun tanks be halted in favor of 90mm gun and 105mm howitzer tanks.(47) It should be noted that the problems with the 76mm and 3" guns did not necessarily involve the weapons themselves: the noses of US armor-piercing ammunition of the time turned out to be excessively soft. These ammunition deficiencies proved that Ordnance tests claiming the 76mm gun could penetrate a Pz.Kpfw.Tiger Ausf.E's upper front hull to 2000yd (1800m) were sadly incorrect.(48) After firing trials at Isigny, France, in July 1944 demonstrated the difficulty the US 76 mm and 3" would have with the Panther, General Eisenhower himself complained that, "Ordnance told me this 76 would take care of anything the Germans had. Now I find you can't knock out a damn thing with it."(49) American armor plate suffered from similar flaws in manufacture until October 1943, when quality control processes were improved.(50)
Combat experience showed the Marines that their light tanks were vulnerable and underarmed, so they made the move to the Sherman medium tank. The Sherman first fought with the Marines at the battle of Tarawa in November 1943.(51) The Sherman was the most powerful tank used in the Pacific Theater, and it proved devastating against Japanese armor. Light and medium tanks mounting flame throwers also proved useful as close assault weapons. Usage of the heavier medium tanks, though, forced the design of more robust landing craft such as the Landing Ship, Tank (LST), since the Sherman's 35-ton (32-metric ton) bulk could not be handled by earlier vessels.(52) Tank-infantry cooperation was dismal in early operations (53), and it wasn't until after the debacles at Guadalcanal and Tarawa that training in this area intensified and matured.(54)
The Army had standardized on the gasoline-fueled M4A3 Sherman, meaning that the Corps could obtain numbers of the diesel-powered M4A2 quicker.(55) The Corps was forced to convert to 75mm gun M4A3s, however, once M4A2 production switched to the M4A2(76)W in mid-1944.(56) The Marines relished the excellent high-explosive power of the 75mm gun's M48 high-explosive shell, and the 76mm gun, while being more effective at armor penetration, fired a weaker HE shell. The Marines eventually accepted a number of 105mm howitzer Shermans once production and support of the 75mm gun tanks had ceased and the Army was concentrating on the M26.(57)
An innovation in infantry vehicles that was perfectly suited to Marine use was the tracked landing vehicle. The first LVTs were modified versions of Donald Roebling's Alligator, which was used as a swamp rescue vehicle in Florida's Everglades. At first the LVT was seen simply as an efficient mechanism of transporting supplies from ship to shore (58), but it wasn't long until a more direct military role as an assault craft was envisioned, and LVTs premiered in this role at Tarawa.(59) LVTs initially used in assault landings were unarmored or fitted with applique armor plates, and the position of the engines in the rear of the vehicle made for a tension-filled dismount over the tall sides. LVT3 and LVT4 remedied that problem by repositioning the engines and adding a rear loading ramp. Armored amphibians were also developed to give the assault craft direct fire support during the landing and immediately after. The armament of the assault amphibians started out as a small 37mm gun on LVT(A)1, but advanced to a 75mm howitizer on LVT(A)4.
As is widely known, the industrial might of the United States was unmatched during World War II. Over 49,000 Sherman tanks were produced from 1942 to 1945 (60), along with almost 14,000 M3 and almost 9,000 M5 light tanks.(61) The US was able to spare over 11,500 light (62) and 26,600 medium tanks (63) for the Allies under the Lend-Lease program. Germany, on the other hand, produced just over 25,000 tanks of all types from 1938 to 1945.(64) Besides a few kept for unit training, the entire production runs of the M5 and M9A1 half-tracks and their variants were also allocated to the Allies through Lend-Lease.(65)
After World War II, the Armed Forces of the United States were again drawn down to skeleton-crew levels: out of the ten regular divisions that made up the Army in 1948, only one was an armored division.(66) The final death knell of the Tank Destroyers was also sounded when the Theater General Board in Europe, after studying the after-action reports of the forty-nine tank destroyer battalions that fought there, recommended that the Armored Force itself accept the more successful components of the Tank Destroyer doctrine and that "the tank destroyers as a separate force be discontinued."(67) The Tank Destroyers were quickly disbanded, and all of the tank destroyer units were decommissioned by 1 November 1946.(68) The Board also recommended that an armored regiment be assigned to each infantry division, while the infantry division's regimental antitank companies be deleted.(69) By implicitly stating that the best antitank weapon was another tank, this recommendation directly defied the earlier attitude that tanks were not to seek out enemy armor.
Postwar, the combination of budgetary constraints that allowed armored vehicles to fall into disrepair and concern over damage medium tanks would cause to Japanese roads while on occupation duty meant that the heaviest tanks readily available to US forces in Japan were light M24 Chaffees. This would haunt the first US forces into Korea after the North's invasion on 25 June 1950: compared to the 225 North Korean T-34-85 medium tanks, the Chaffees were wholly inadequate. American medium tanks were rushed to the theater after many were reconstructed in Japan, which allowed the M24s to resume their usual role of reconnaissance and flank security.(70) The M4 Sherman in its later guises (i.e., 76mm gun tanks and 105mm howitzer tanks) proved useful in Korea, and the 76mm gun tanks were able to hole the T-34-85 at combat ranges.(71) The more powerfully armed M26 and M46 tanks proved just as capable at antitank work.(72) The war entered a more static phase after 1950, where tanks were often used as artillery, for bunker reduction, and for infantry support. Sherman tanks were often preferred over M26 Pershings during this time, since the M4s could climb terrain better than the newer heavier tanks. The Sherman was still the most numerous tank in service in Korea when the armistice was signed in 1953.(73) Among the recommendations to come out of the Korean War regarding armored forces was a suggestion in 1951 by the Operations Research Office (ORO) of the Far East Command to reinforce combined arms training, since at times the cooperation between armor and infantry left much to be desired. A 1954 ORO report recommended better night training and night vision equipment.(74)
America's strategic emphasis on atomic weapons and the subsequent Air Force domination of the defense budget somewhat stunted tank development during the Cold War. However, some of the most successful designs ever churned out by the US were produced during this time. The North Korean invasion, and the possibility that it might have led to another world war, sparked a forecasted shortage in medium tanks that the US scrambled to head off. The M47 Patton 47 was then created by mating the turret from the T42 tank project with a hull based on the M46.(75) The M47 was supposed to be no more than an interim design until the M48 could be unveiled, but almost 9,000 M47s were eventually constructed.(76) The M48 was developed into the M60, which was the United States' premier tank for the next twenty years and faced off against impressive Soviet vehicles such as the T-64 and T-80 until the M1 Abrams was introduced.
Infantry was not left behind, so to speak, during the Cold War years. From their trundling beginnings, tanks had quickly gained enough power and speed to necessitate motorized transportation for the accompanying footsoldiers. In the Second World War, the US had utilized half-tracks for this purpose. These vehicles were used for reconnaissance as well as infantry transport, and would start the long tradition of infantry carriers being used for a multitude of roles. The advent of variable-timed artillery shells and atomic weapons, however, obsoleted the half-tracks with their open troop compartments.(77) The development of fully-enclosed and fully-tracked infantry carriers started even before the end of the war. The armored utility vehicle M44 was the first purpose-built design, but was cancelled due to its very large size and the disappearance of funds following the end of World War II.(78) The armored infantry vehicle M75 was smaller than its predecessor, but there were concerns that it was excessively expensive during the budgetarily lean atomic weapons years.(79) The M59 armored personnel carrier replaced the M75, and thankfully for the Army cost about one-fourth as much as the M75.(80) The M59 achieved this price difference largely by using commercial GMC truck engines instead of the specialized powerplant of the M75, which was related to that found in the 76mm gun tank M41 Walker Bulldog.(81) While being cheaper than the M75, the M59 was actually heavier. The search for an air-transportable armored personnel carrier culminated in 1960 with the introduction of the M113, which with its aluminum rather than steel armor weighed about half as much as the M59. The M113 became the most-produced American armored vehicle in history, and was modified to fill an almost uncountable number of roles. The basic shape of the APC changed little from the M44 to the M113: they were all essentially armored boxes on tracks. Also, the basic mission of these modern armored personnel carriers harkened back to the half-tracks of World War II: they were to transport infantry as close as possible to their objective, where the troops would dismount and fight on foot.(82) The lack of the ability for the infantry to fight while mounted would drive the development of a new class of infantry carrier which would ultimately appear as the M2 Bradley infantry fighting vehicle.
The armored forces of the United States got another taste of jungle fighting in a country superficially similar to the Koreas when they were deployed to Vietnam. The main medium tank that would fight with American units in Vietnam was the M48A3 Patton, although small numbers of M48A1s were issued due to a shortage of M48A3s following the 1968 Tet offensive.(83) The newer M60s with their 105mm guns guarded the Fulda Gap in Germany against Soviet armor. The M48A3, however, was plenty of tank for Vietnam. Its 90mm gun was able to fire a variety of ammunition, and its bulk and 750-horsepower engine allowed it to break trails through the thick jungle. The M113 APC also served in Vietnam, and it was the South Vietnamese who introduced new tactics in the use of these APCs. They mounted two more machine guns on either side of the rear cargo hatch, provided the commander and extra machine gunners with armored shields, and used these modified M113s much like light tanks.(84) This conversion was so successful that standardized kits for these Armored Cavalry Assault Vehicles were procured from the US and sent to Vietnam in 1966.(85) The M551 Sheridan was deployed to Vietnam in 1969. The M551, designed for the European theater as a light reconnaissance and airborne assault vehicle, proved fast and agile, but very vulnerable to mines and handheld antitank weapons.(86) The 152mm gun-launcher proved devastating, especially with its antipersonnel ammunition, however incomplete combustion of the propellant casing presented problems. The closed-breech scavenging system was developed to resolve this dangerous situation.(87) The combustible casing of the ammunition also proved sensitive to the tropical humidity and prone to detonation upon penetration of the vehicle's armor.(88)
Initially, though, it appeared that armored forces would not be sent to Vietnam: American commander Gen. William Westmoreland sent a message to the Army Chief of Staff in July 1965 saying, "except for a few coastal areas ... Vietnam is no place for either tank or mechanized infantry units."(89) When the 1st Infantry Division deployed to Vietnam, its tanks were kept home and its mechanized infantry forces were transformed into dismounted infantry.(90) However, a study completed in 1967 showed that tanks could maneuver in 61% of the country in the dry season and 46% during the monsoon season; APCs could travel around 65% of Vietnam regardless of the rains.(91) The importance of armored forces in the Vietnam War was illustrated by the fact that, although their utility in the mountainous jungles was at first far from taken for granted, the armored units of formations pulling out of Vietnam were kept in country until last, buying more time for the American "redeployment."(92)
The development of the M60's replacement would entail three vehicle programs and almost two decades of work. Three years after the first M60s were accepted, the MBT70 program was begun.(93) MBT70 was to provide a common tank for the US and West German armored forces, and the vehicle itself was stuffed with high technology features. It was hoped that by sharing the development effort and costs that the complex MBT70 could be produced more cheaply than its Soviet counterparts.(94) MBT70 was to be armed with an automatically loaded 152mm gun-launcher capable of firing the Shillelagh antitank missile. It featured a 3-man crew, all of whom were in the turret. The driver was interestingly positioned in a counter-rotating cupola in the turret's front corner. A laser rangefinder and stabilization helped assure accuracy. MBT70 ran on a hydropneumatic suspension that allowed the vehicle to crouch or raise one end of the tank to better take advantage of hull-down positions. Problems, however, plagued the MBT70 program from the beginning.(95) Difficulties with English-German translations, metric to English measurement conversions, and differences between German and American manufacturing and designing practices caused considerable headaches before the first tanks were even designed.(96) The development costs spiraled to unacceptable levels, and MBT70 was killed in 1970, leaving the Germans and Americans to go their separate ways.(97) The US chose to give the MBT70 another chance, but this time as an austere vehicle with toned-down technological gizmos. This project was dubbed XM803, and it featured a less powerful engine, lacked the complex hydropneumatic suspension, and was protected by a simpler armor array than MBT70. Congress was especially cost-conscious after the Air Force's accounting fiasco with the C-5 Galaxy transport plane and difficulties with its F-111 fighter/bomber, so as the XM803 was being estimated to cost three to four times as much as an M60A1 (98), and with the Shillelagh missile system proving troublesome on the M551 and M60A2 tanks, XM803 was cancelled in December 1971.(99)
By then, the M60 was a decade old, and the Army was forced to start fresh on its replacement. It was decided that the new vehicle, named XM1, would be armed with the conventional 105mm gun M68, feature a four-man crew including a human loader, and run on a conventional suspension.(100) The new tank would emphasize crew survivability above all else (101), and to this end a new type of armor designed by Dr. Gilbert Harvey at Britain's Fighting Vehicles Research and Development Establishment near Chobham would be used.(102) This armor was composed of a matrix of ceramics and steel layers, and was very effective against high-explosive antitank warheads as well as kinetic energy projectiles. However its protective properties needed to be balanced against its heavy physical weight. Army Chief of Staff Gen. Creighton Abrams himself made the decision to use the American version of this armor on the frontal arc of the tank, since in his opinion its promise of extra protection was more important than the weight penalty.(103) This armor is what gives the tank its characteristically slab-sided look. The crews of the new tank were also protected by the layout of its ammunition stowage, with the majority of the main gun ammunition in the turret bustle behind a bulkhead. If the ammunition ignited, blowoff panels in the turret bustle's roof would vent the explosion out of the tank while the bulkhead doors protected the crew from danger. The XM1 was powered by a novel gas turbine engine that gave the vehicle an advantage in acceleration over conventional diesels.
Once fleshed out, the M1 prototypes suffered from problems with track shedding, as well as engine and transmission failures, but these were eventually solved.(104) Tests in the mid-1970s between the 105mm M68, a British 110mm gun hampered in performance by using APDS vice APFSDS ammunition (105), and a German Rheinmetall 120mm smoothbore gun proved that the M68 was still a dangerous weapon thanks to improved ammunition technology, but the 120mm gun was full of growth potential. The early M1 tanks were armed with the old M68 since it was feared that the delay and expense involved in producing the 120mm weapon would scare Congress into cancelling the program, but the 120mm was eventually adopted on the M1A1 in 1985.(106) When the finished product finally emerged on 28 February 1980, after almost twenty years of work, two failed programs, and even a competition with the West German Leopard 2, it was the most powerful and advanced tank the United States had yet produced. The M1's fire control system, which included a laser rangefinder and thermal imaging system, allowed it to engage targets on the move cross-country in any weather. Its composite armor provided the crew with enhanced protection, and features such as the ammunition bustle further shielded the crew from injury should a penetration occur. Its turbine engine proved reliable, and endowed the tank with outstanding performance. The M1 tank gave the US the capability to practice an entirely new warfighting doctrine.
Following World War II, the Marines were forced to modernize their tank fleet, and although they realized that designs with more armor than their venerable Shermans were needed, they balked at the increase in weight that the extra protection imposed.(107) The Pershing was only fully integrated into Marine armored units in 1949, and this seemed a wise choice after the North Korean invasion with its spearhead of T-34-85s.(108) The M46 started replacing the Marines' Pershings in July 1951, M47s began arriving in October 1951, and the M48 entered service with the Marines in 1954.(109) The Marines also retained heavy tanks long after the Army had given up on the idea. The M103 was racked by teething problems upon its introduction, and the Marines alone developed the M103A1. The Army was so suitably impressed with the modifications that it borrowed 72 M103A1s for its heavy tank battalion in Europe (110), and M103A2 remained in the Marine Corps arsenal until 1972. The cancellation of XM803, which it was hoped would replace the Marines' fleet of M48s, forced the Marines to acquire the M60A1 in 1974.(111) The Army's standardization on the M1 Abrams tank again forced the Marines to change for the sake of logistical commonality, and the M1A1 totally replaced Marine M60A1s by 1996.(112) The M1A1 is expected to serve with the Marines until 2020.(113)
Throughout the 1960s and '70s, work was conducted on a new Army infantry vehicle. The then-current crop of APCs was not conducive to mounted combat, which was thought to be necessary on a battlefield contaminated by nuclear, biological, and chemical agents.(114) Work on the joint US-West German MBT70 project also seemed to necessitate a new infantry vehicle that could keep up and fight with the highly-mobile tank.(115) The US had been working on its new infantry vehicle for almost a decade when the Soviet BMP-1 was started into series production in 1968.(116) BMP-1 was much more heavily armed than contemporary APCs, with a 73mm main weapon and integral antitank missile launcher. It was also fitted with firing ports and periscopes in the passenger compartment to allow for mounted combat in an NBC environment. Compared to M113, BMP-1 was a major threat. The US, however, was still trying to pound out a doctrine for its new infantry vehicle, and therefore as well the vehicle's characteristics. A hesitancy to decrease the number of men in the mounted rifle squad and a requirement for amphibious capability would dog the design of the American infantry fighting vehicle to the end.(117) The very authority over mechanized infantry was also debated upon, with the Infantry and Armor Schools both claiming responsibility.(118) In the end, mechanized infantry became Infantry's burden. Complicating the program immensely was the merger of the future IFV with the struggling Cavalry scout vehicle in late 1975.(119) What eventually emerged were the Bradley fighting vehicles, the M2 IFV and M3 cavalry fighting vehicle.
The new vehicle was controversial in both its guises. Since the US Army had returned its attention after Vietnam to facing off with the Soviet Union and its huge park of armored vehicles, the proliferation of American antitank weapons was imperative. Thus, the Bradleys were fitted with a twin TOW missile launcher, giving each mechanized squad a heavy, long-range antitank weapon. This was not universally viewed as a bonus, as some soldiers claimed the ATGM added unnecessary complication and distraction. Cavalry troops also railed against the large size and signature of the M3, which was a definite disadvantage when performing reconnaissance.(120) The scouts certainly had cause for concern here, since a Bradley is dimensionally larger than a Sherman tank. The infantry were also nonplussed with the technical complexity of the vehicle, necessitating that an infantry squad leader essentially also become a tank commander.(121) The Bradley fighting vehicle had defenders as well, though. Its proponents cited its increased firepower, armor protection, and mobility over the previous alternative, the M113 APC.(122) At the heart of all the controversy was the very definition of an IFV. Infantry fighting vehicles are a hybrid design, bridging the gap between the "battle taxi" armored personnel carriers and infantry-supporting light tanks. Designing a vehicle and doctrine to fulfill this complex niche occupied the US Army for over fifteen years.
Marine infantry was changing, too. The introduction of the helicopter and the associated notion of vertical envelopment, as well as the tradition of being a light infantry force, led the Corps to embrace the light armored vehicle. For this purpose an eight-wheeled version of General Motors Canada's version of the MOWAG Pirate LAV was procured.(123) The vehicles were thought necessary to keep the Marine infantry capable of performing maneuver warfare operations, and the LAV was introduced to the Corps in 1983.(124) A family of vehicles was produced on the LAV chassis, including, in addition to the standard 25mm gun turret vehicle, command, mortar, and TOW vehicles. The LAV battalions were initally used simply as land-based carriers; infantry was not added permanently to the organization until the late 1980s.(125)
Tracked landing vehicle designs progressed after World War II to fully-enclosed vehicles like the LVTP5 and the LVTP7, which has been in service for over forty years. Its replacement, the Expeditioinary Fighting Vehicle, was under development by General Dynamics Land Systems Division, and was expected to enter low-rate production by 2010. The EFV was utilize a planing hull to skim along the ocean's surface, making over-the-horizon assaults faster and therefore more viable.(126) Due to budgetary concerns, however, the program was cancelled in January 2011.(127) In its stead, the Marines are looking to develop a cheaper amphibious combat vehicle as well as a wheeled armored personnel carrier; a service life extension program will keep the venerable AAVP7 in service until the new vehicles are fielded.(128)
America's newest generation of armored vehicles, including the M1 tank and Bradley fighting vehicles, gave rise to an entirely new doctrine of war. Developed and improved from 1973, AirLand Battle finally emerged in 1982 and emphasized combined arms warfare and tactical flexibility. Free-thinking subordinates were to quickly make and execute decisions based on their commanders' intentions. AirLand Battle was characterized by four concepts: initiative, depth, agility, and synchronization. Forces were intended to achieve and retain the initiative, be positioned in depth with relation to time and space, react to situations faster than the enemy, and synchronize combined arms so that an enemy's reaction to one maneuver would put him at risk from another.(129) AirLand Battle replaced the Active Defense concept, which espoused that defending units would maneuver to the flanks of a penetration and chip away at the attack until it was halted.(130) AirLand Battle was put to the test in Operation Desert Storm in early 1991. A coalition army was built up over five months (131), and a long air campaign decapitated the Iraqi armed forces. America's newest armored vehicles, especially the M1 tank and Bradley fighting vehicles, were venerated in the subsequent ground campaign. American forces were better trained, better led, better able to communicate and utilize information, and fighting with better equipment than their opponents. The fire and maneuver practice preached by AirLand Battle consistently took the Iraqis by surprise. This combination led to an Iraqi defeat in under five days.(132)
Since the Vietnam War, US armored units had been prepared to take on the hordes of tanks possessed by the Soviet Union, and its collapse in December 1991 threw the US Armed Forces into a semi-limbo state. The Persian Gulf War of 1991 had proved that the doctrinal concepts, training, and equipment developed to defeat the Soviet armies were viable and effective against an opponent modeled after the Soviet Union, but the amount of time it took to build up the forces necessary to evict Iraq from Kuwait seemed prohibitive. A lighter, more deployable force was deemed necessary to respond to the type of threats envisioned for the future. The future for US armored units appears to be a transformation to lighter, more easily supported vehicles. To this end, the Future Combat System (FCS) was being developed and was expected to enter service around 2012.(133) The FCS was to consist of a family of vehicles, both crewed and unmanned, that would be able to be configured for a variety of missions.(134) The manned vehicles were cancelled in June 2009, however, and the rest of the program was integrated into the Army Brigade Combat Team Modernization program.(135) The Abrams tank is still expected to serve until the year 2050, however.(136) To put that date into perspective, it will make the Abrams 70 years old when it is retired. Conversely, only just over 63 years elapsed from the first action of tanks in late 1916 until the Abrams's intoduction in early 1980.
To expedite this shift towards a more deployable armored force, an Interim Armored Vehicle (IAV) in the vein of the FCS was procured as a joint venture from General Motors and General Dynamics Land Systems Division. The IAV consists of a family of vehicles, including a mobile gun system armed with a 105mm gun, an infantry carrier armed with a .50cal machine gun and an automatic 40mm grenade launcher, mortar, and command vehicles. It was chosen to base the IAV on the eight-wheeled General Motors LAV III, and the vehicle has been named Stryker after two Medal of Honor recipients.(137) One of the requirements of the IAV was that it should be able to be transported in C-130 cargo aircraft, which are the most numerous transport planes in the USAF. However, eight of the ten IAV variants as designed were too heavy to fly on a C-130; designers had to look at ways to make the vehicles lighter.(138) Even making the target weight, however, flight distance and airfield restrictions will still apply, especially if applique and reactive armor suites are added to the vehicles.(139)
The United States military has had a long, if at times strained, relationship with mechanization and armored vehicles. America has historically enjoyed a reputation for relatively comfortable, reliable, but inadequate tank designs. This assertion does not always hold true, and inadequacies that did exist can become at least a bit more understandable when circumstances surrounding their existence are explained. The US has used armored vehicles for over eighty years, and its AFVs have necessarily been involved in the largest conflicts in history. From their inauspicious beginnings in European-built tanks, the tank men of the US have crewed the most important and among the most-produced vehicles ever. Flawed doctrinal concepts hampered tank development in World War II, and armored vehicles were intially dismissed as being unnecessary in Vietnam, but the power and utility of American tankers and their mounts were demonstrated in the 1991 Persian Gulf War. The collapse of the USSR and the anticipated threat of low-intensity conflicts that require lethal forces to arrive at the scene quickly have spurred a trend away from the heavy main battle tanks of the Cold War to lighter, more deployable, and technologically sophisticated vehicles for the future. American fighting vehicles have come a long way since their inception, and today the US remains at the forefront of AFV development. One hopes, however, that the powers that be in the US military remember that high-tech weapons are not the crux of an army, and that without highly trained and motivated soldiers acting in accordance with innovative and sound doctrines, even the most technologically sophisticated fighting vehicles are no more than white war elephants.
