As World War II’s reluctant allies became Cold War adversaries, the United States found itself facing multiple – and decidedly different – combat scenarios for tank warfare. The primary focus remained on the “cold” front, where U.S. and NATO forces faced thousands of Soviet and Warsaw Pact tanks in Europe. But Korea – and then Vietnam – provided extremely different environments, enemy forces and tactics on “hot” fronts in which the Soviet Union did not commit itself to direct conflict with the United States.

To the dismay of many veteran tankers in the 1950s, two new, fast evolving technologies were being touted by the Eisenhower administration to quickly – and more cheaply – counter the Soviet/Warsaw Pact European theater superiority in numbers and types of armor: Battlefield nuclear weapons and rockets and missiles.

“The administration recognized early on there was no way in time of peace, after Korea, you could sustain wartime mobilization of industry and the population – not in terms of cost or political support – without a real shooting war. Atomic weapons were a less costly means of keeping the Soviets at bay,” said Dr. Robert S. Cameron, Armor Branch historian at the Army Armor Center at Fort Benning, Ga. “Ground forces in Europe, however, still had to defend West Germany, so the focus there remained on armor, armored divisions and the forces involved with that.”

“The design focus in the mid 1950s was simple – identify the target as far away as possible, then acquire, engage and kill it, preferably with one shot. To do that, you needed better optics, fire control systems and ammunition. But with basically the entire national defense establishment embracing atomic weapons, those wedded to more conventional concepts often had trouble getting funding.”

Also high on the list for ground forces was a new look at what armor had to do in combat and what kind of technologies were needed to overcome the West’s numerical disadvantage.

“The design focus in the mid 1950s was simple – identify the target as far away as possible, then acquire, engage and kill it, preferably with one shot. To do that, you needed better optics, fire control systems and ammunition. But with basically the entire national defense establishment embracing atomic weapons, those wedded to more conventional concepts often had trouble getting funding,” Cameron said.

“It was a very evolutionary process, moving from the M46 to the M47, then the M48 and, by about 1960, an M48 upgrade called the M60. There wasn’t a lot of fundamental change, just component upgrades. The M48, for example, introduced a ballistic computer and better optics, in line with acquiring targets at a greater range. At the same time, you also had people working on a revolutionary path of development, trying to incorporate missiles, rockets, different platform configurations and other new technologies. Most of these designs never got out of prototype.”

“The Shillelagh was capable of destroying any known main battle tank on the planet at pretty respectable distance. Put that on a light armored platform and you have a powerful weapon system that can be air-dropped and, when not firing a missile, you have a 150mm gun tube that also can fire a 152mm conventional round. So from the armor standpoint, it’s wonderful – light, air-droppable, state-of-the-art anti-tank protection and an incredibly powerful bunker-busting, canister-throwing conventional weapon system.”

One new U.S. tank that did emerge from the 1950s was the M551 Sheridan, a light tank designed to replace the M41 as an Armored Airborne Reconnaissance Assault Vehicle.

“If you put a bunch of lightly armed paratroopers behind the enemy, how do you protect them if counter-attacked by a heavy armor force? The answer was some mobile anti-tank capability of their own,” Cameron explained. “Combine that with growing experimentation in missiles and rockets and you get the Sheridan, which mounted a gun missile system – the Shillelagh – on a relatively light aluminum chassis.

“The Shillelagh was capable of destroying any known main battle tank on the planet at pretty respectable distance. Put that on a light armored platform and you have a powerful weapon system that can be air-dropped and, when not firing a missile, you have a 150mm gun tube that also can fire a 152mm conventional round. So from the armor standpoint, it’s wonderful – light, air-droppable, state-of-the-art anti-tank protection and an incredibly powerful bunker-busting, canister-throwing conventional weapon system.”

The Sheridan entered service in the 1960s and was fielded to Vietnam around mid-decade as part of President Lyndon Johnson’s massive increase in U.S. presence there. While it initially suffered from limited funding and an increasingly long concept-development-fielding chain, it also benefited from the Kennedy/Johnson administrations’ shift away from a near total dependence on atomic deterrence and the decision to add a powerful conventional deterrent, as well. That increased funding for a more flexible response to the ingrained Cold War view that Soviet mechanized capability was constantly increasing.

“With a return to conventional systems and working to improve them, the M60 was fielded in greater numbers, the M48 went through multiple upgrades and the Army shifted finally from gas to diesel engines, providing greater operational radius to tanks,” Cameron said. “Throughout this period, the focus was still on Central Europe and dealing with the Soviet horde. There was not a lot of attention in the early Sixties on other parts of the planet – such as Southeast Asia – by the armored community.”