• START I (Strategic Arms Reduction Treaty) was a bilateral treaty between the United States of America and the Union of Soviet Socialist Republics (USSR) on the reduction and limitation of strategic offensive arms. 
  • The treaty was signed on 31 July 1991 and entered into force on 5 December 1994. The treaty barred its signatories from deploying more than 6,000 nuclear warheads atop a total of 1,600 inter-continental ballistic missiles (ICBMs) and bombers.
  • New START treaty: New START replaced the Treaty of Moscow (SORT).  Under terms of the treaty, the number of strategic nuclear missile launchers will be reduced by half. 
    • It was signed on 8 April 2010 in Prague,and after ratification entered into force on 5 February 2011.
    • This treaty is formally known as Measures for the Further Reduction and Limitation of Strategic Offensive Arms.