New START

New START (Russian abbrev.: СНВ-III, SNV-III from сокращение стратегических наступательных вооружений "reduction of strategic offensive arms") is a nuclear arms reduction treaty between the United States and the Russian Federation with the formal name of Measures for the Further Reduction and Limitation of Strategic Offensive Arms. It was signed on 8 April 2010 in Prague, and after ratification it entered into force on 5 February 2011.

New START replaced the Treaty of Moscow (SORT), which was to expire in December 2012. It follows the START I treaty, which expired in December 2009; the proposed START II treaty which never entered into force; and the START III treaty, for which negotiations were never concluded.

The treaty calls for halving the number of strategic nuclear missile launchers. A new inspection and verification regime will be established, replacing the SORT mechanism. It does not limit the number of operationally inactive nuclear warheads that can be stockpiled, a number in the high thousands.

On 21 February 2023, Russia suspended its participation in New START. However, it did not withdraw from the treaty, and clarified that it would continue to abide by the numerical limits in the treaty.

The treaty limits the number of deployed strategic nuclear warheads for each party to 1,550, which is down nearly two-thirds from the original START treaty, as well as 10% lower than the deployed strategic warhead limit of the 2002 Moscow Treaty. The total number of deployed warheads could exceed the 1,550 limit by a few hundred because only one warhead is counted per bomber regardless of how many it actually carries. The treaty also limits the number of deployed and non-deployed intercontinental ballistic missile (ICBM) launchers, submarine-launched ballistic missile (SLBM) launchers, and heavy bombers equipped for nuclear armaments to 800. The number of deployed ICBMs, SLBMs, and heavy bombers equipped for nuclear armaments is limited to 700. The treaty allows for satellite and remote monitoring, as well as 18 on-site inspections per year to verify limits.

The obligations must be met within seven years from the date the treaty enters into force. The treaty will last ten years, with an option to renew it for up to five years upon the agreement of both parties. The treaty entered into force on 5 February 2011, when the United States and Russia exchanged instruments of ratification, following approval by the U.S. Senate and the Federal Assembly of Russia. The United States began implementing the reductions before the treaty was ratified.

Documents made available to the U.S. Senate described^{[clarification needed]} removal from service of at least 30 missile silos, 34 bombers, and 56 submarine launch tubes. Missiles which are removed would stay intact, and bombers could be converted to conventional use. Four of the twenty-four launchers on each of the fourteen ballistic missile nuclear submarines would be removed, and none retired.

The treaty places no limits on tactical systems, such as the Lockheed Martin F-35 Lightning II, which will most likely be replacing the F-15E and F-16 in the tactical nuclear delivery role.