Salt ( the Strategic Arms Limiting Talks)
The salt conferences where a series of negations and treaties between the US and the USSR that limited the production and development of nuclear arms. The original salt talks where held in Helsinki, Finland in and resulted in freezing the number of ballistic missiles. It allowed submarine launched ballistic missiles only if a intercontinental missile was dismantled. The last result of the treaty forced both countries to have only two sites protected by ABS (Anti-Ballistic Systems).
SALT II
Salt II is a continuation of the SALT talks where the US and the USSR that focused on the loopholes in SALT that allowed for strategic nuclear weapons, namely Multiple independently target-able reentry vehicles such as the one pictured below. It succeeded in banning new missile projects and essentially freezing the amount of strategic nuclear systems. To give you an example of some weapons that fall in this category , they can include the before mentioned MIRV's, bombers (especially stealth bombers). The treaty was agreed upon in 1979 but the senate did not aprove it. Still the president was honoring the treaty. When the USSR inaved afganastan the US pulled thier support of the treaty fully ignoring allof it terms
Politcal Cartoon
Here we have a cartoon of the US and the soviets You can see that they both seem to agree on the document in their hand (SALT II) but behind their back are missiles. This represents the attitude the countries are taking with this agreement, Both countries want people to see the they but they still want their new nuclear tech)
Conclusion
The salt treaties allowed for the US and it's citizens to have some peace of mind that nuclear war was far off, and the arms race slowed but with the invasion of Afghanistan the US again worried about the USSR and began to withdraw treaties. and tesions rose, read my article about the soviet inavsion of Afganastan to find out more