The last phase of the Cold War unfolded during 1989-1991. Determined to move "beyond containment" in relations with the Soviet Union, President George Bush challenged Mikhail Gorbachev to join the United States in ending the East-West conflict and the arms race. As Moscow reached new agreements with Washington and began withdrawing it troops and dismantling its massive military machine in Eastern Europe, its erstwhile allies, contrary to Gorbachev's expectations, rejected communism once and for all. The collapse of communism in Eastern Europe foreshadowed and to some extent accelerated its collapse in the USSR. Gorbachev found himself battling on two fronts at once, as he tried to maintain the USSR's superpower status and reform the Soviet system in what he described as a "battle to the death" with reactionary forces. That battle ended in mutual annihilation after the unsuccessful coup of August 1991, bringing about first the destruction of the old imperial order and later Gorbachev's presidency. The USSR then entered its death spiral and officially ceased to exist as of 31 December 1991.