The Nuclear Non-Proliferation Treaty (NPT) was opened for signature in 1968 and entered into force in 1970. According to the United Nations, the organization responsible for the legislation, "the Treaty represents the only binding commitment in a multilateral treaty to the goal of disarmament by the nuclear-weapon States." Five of the states party to the treaty are considered nuclear weapon states: the United States, Russia, the United Kingdom, France, and China.
However, the United States has been criticized on several occasions for violating the provisions of the treaty when negotiating arms sales with India, a recognized nuclear state that has refused to sign the NPT. In 2008, President Obama stated that he wished to "strengthen the Nuclear Non-Proliferation Treaty so that nations that don't comply will automatically face strong international sanctions." Additional nuclear states that are noticeably absent from the list of signatures are Israel and Pakistan. The treaty, set to be assessed every five years, will be reviewed in May of this year.
With regard specifically to negotiations between Russia and the United States regarding US-Russia nuclear relations, one successful treaty is the Strategic Offensive Reductions Treaty (SORT). The goals of the legislation are to limit the number of warheads each state has within its nuclear arsenal. The treaty, which expires in 2012, requires semi-annual negotiations of the provisions of the document.