START II
START II, the "STrategic Arms Reduction Treaty" was signed by George H. W. Bush and Boris Yeltsin in January 1993, which banned the use of MIRVs. It followed START I.
The historic agreement started on June 17, 1992 with the signing of a 'Joint Understanding' by the presidents.[1] (http://www.fas.org/nuke/control/start2/)
However, it was abandoned because of a U.S.-Russian dispute over U.S. plans for a ballistic missile defense system.
See also:
de:START