This is the tactical nuke developed by US to use straight in the battlefield and achieve specific objectives. The Cold War era had a tense atmosphere with both the NATO and Warsaw Pact nations exercising an open second strike doctrine and not ruling out first strike either. Both US and USSR had piled up nuclear arsenal large enough to destroy the Earth several times over and that was just pure insanity. Nowadays, most of the eight primary nuclear-powered nations are limiting their WMDs and relying on missile defense systems to protect their areas. But, back in the 50s, 60s and 70s, the security conundrum of the world was such that both the capitalist and socialist axis did weapon research and development without considering the repercussions and sensitivity of these weapons.
The M-28/29 “Davy Crockett,” probably the smallest nuke launcher ever built was one of those weapons. It was to be loaded with the tiny M54 nuke that could effectively be stored in a backpack. Its range was just over two and a half miles and could be made shorter even than this. The weapons grade nuclear fissile material used in the warhead was very low yield and the resulting blast of the strike was much smaller than an average armament used in a ballistic missile. Here is what you can expect from the smallest nuclear warhard ever used:
So, its 51-pound payload could effectively level a bridge, a small anti-aircraft or anti-missile installation as well as dams or other infrsatructures of strategic importance. This was the primary objective doctrine in the military for its usage in the latter years. However, it was originally meant to create deterrence for the heavy troop deployment in the then East Germany by the Soviets. The Fulda Gap was one of the most crucial areas where enemy attacks were reported by intelligence every now and then. So, these tactical nukes were an ultimate deterring force in keeping them at bay for so long.
However, the sheer danger of having a group soldiers carrying a live atomic bomb in their backpacks wasn’t realized by the pentagon. They were soldiers and not robots and there was no off-switch in case one of them went rogue. But, the military decided to take them and deployed them for decades even though they weren’t ever used. With the dismemberment of the Soviet Union and the successful common sense Strategic Arms Limitation Talks between the nuclear powers, the nuclear stockpiles were significantly reduced and other confidence-building measures were introduced and implemented by both parties. However, the countries relatively new to the nuclear era like North Korea, India, Pakistan and Israel have no intentions of giving away their weapons of mass destruction as they think of them as necessary deterrence. Almost all of them are actively pursuing tactical nukes and have probably developed them by now. US and Russia learned about it the hard way then the Cuban missile crisis almost led to a full-scale nuclear war. Afterward, they have been sensible about it. The emerging nuclear powers especially India and Pakistan need to think about it rationally and stop arms race in the region. Arms race leads to inequality of firepower and it leads to the smaller nations developing irresponsible weapons like these tactical nukes!