Strategic Arms Reduction Treaty (START) refers to certain arms control agreements designed to reduce the numbers of long-range nuclear weapons. The United States and the Soviet Union signed the first, START I, in July 1991. START I called for a reduction in the number of long-range nuclear warheads and bombs held by each country by about one-third over a period of seven years.
In late 1991, the Soviet Union broke apart. Afterward, the formerly Soviet weapons were in the newly independent countries of Belarus, Kazakhstan, Russia, and Ukraine. The United States ratified START I in 1992, and the four former Soviet republics with nuclear weapons did so by 1994. The treaty took effect in 1994. By the end of 1996, Belarus, Kazakhstan, and Ukraine turned over all their nuclear weapons to Russia.
The United States and Russia signed START II, the second START agreement, in 1993. START II aimed to cut the total number of U.S. and formerly Soviet long-range nuclear warheads and bombs to less than half that proposed by START I. The United States and Russia would each be left with 3,000 to 3,500 such weapons. To take effect, START II required ratification by both countries, and the beginning of the implementation of START I. The United States ratified START II in 1996. Russian leaders approved START II in 2000, but only after making changes in it. The United States did not ratify the changes, and the treaty never went into effect. The START I agreement expired in December 2009.
In 2010, Russian President Dmitry Medvedev and U.S. President Barack Obama signed an agreement, known as New START, which aimed to reduce long-range nuclear weapons by 30 percent over seven years. The U.S. Senate ratified the treaty in December, and the Russian parliament did so in January 2011. The New START treaty was set to expire after 10 years. In 2021, it was extended for an additional five years. However, in 2023, Russian President Vladimir Putin announced that Russia was suspending its participation in the New START treaty.
