What did it do?: Aimed to restrict nuclear weapons to only Britain, France, China, the USA and USSR.
Why was it flawed?: Because India, Pakistan and North Korea all eventually gained nuclear weapons and this treaty did not restrict the two superpowers nor Britain, France or China. This meant that the arms race could continue.
Strategic Arms Limitation Talks (SALT 1)
Date: 1972 (talks finished)
What did it do?: Aimed to limit the number of strategic ballistic missile launchers and allowed submarine-launched ballistic missile (SLBM) launchers only after the same number of older intercontinental ballistic missiles (ICBM) and SLBM launchers had been dismantled.
Why was it flawed?: Because it didn't limit the amount of warheads on the missiles and so the superpowers just increased the warhead capacity of their missiles and so avoided any real control which the treaty could possibly have exerted.
Strategic Arms Limitation Treaty (SALT2)
Date: 1979(agreement reached)
What did do?: Aimed to reduce all nuclear strategic forces across all delivery systems on both sides.
Why was it flawed?: Because it was never ratified by the USA because of the Soviet invasion of Afganistan.
Anti-Ballistic Missile Treaty
What did it do?: Aimed to limit the number of anti-ballistic missile systems of each superpower to two each.
Why was it flawed?: Eventually the wording became debatable and so the superpowers continued developing counter-tactical ABM's.
Strategic Arms Reduction Treaty (START1)
What did it do?: Barred its signatories from deploying more than 6,000 nuclear warheads atop a total of 1,600 ICBMs, inter-continental ballistic missiles, and bombers.
Why was it flawed?: It wasn't.
Strategic Arms Reduction Treaty (START2)
What did it do?: Aimed to ban the use of multiple independently targetable reentry vehicles on intercontinental ballistic missiles.
Why was it flawed?: Because the Duma only conditionally ratified it and the USA never fulfilled these conditions.
Date: 1963(signed and ratified)
What did it do?: Barred the USA, USSR and Great Britian from conducting nuclear tests in the atmosphere, underwater or in space.
Why was it flawed?: Because all parties had the ability to conduct tests underground and this was not disallowed under the treaty and so nuclear arms production and tests could continue. Both the USA and the USSR broke the treaty at various points anyway.