The SALT I talks began in 1969, and led to the Anti-Ballistic Missile Treaty in 1972, which ultimately limited the U.S. and U.S.S.R. to one defensive missile site each, with no more than 100 missiles per site. This included both ABM interceptor missiles as well as launchers. Originally, the agreement made by the Nixon administration and the Soviet Union stated that both of the two nations were each allowed to have two ABM defensive systems present in their own countries. The goal was to effectively have one ABM defense system located near each nation's capital city as well as another ABM defense system placed near the nation's most important or strategical ICBM field. This treaty allowed for an effective form of deterrence for both sides as if either side were to make an offensive move, the other side would be capable of countering that move. However, a few years later in 1974 both sides reworked the treaty to include only one ABM defensive system present around an ICBM launch area or the nation's capital city. This occurred once both sides determined the other side was not going to construct a second ABM defensive system. Along with limiting the amount of ballistic missile defense systems each nation could have, the treaty also stated if either country desired to have a radar for incoming missile detection, the radar system must be located on the outskirts of the territory and must be aligned in the opposite direction of one's own country. This treaty would end up being the precedent set for future missile defense programs, as any systems that were not stationary and land-based were a violation of the treaty.