In January 1991, the Armenian Supreme Soviet decided not to participate in Gorbachev's planned referendum on preserving the Soviet Union. In March the parliament announced that, instead, the republic would hold its own referendum in September, in compliance with the procedure outlined in the Soviet constitution for a republic to secede. Although literal compliance would mean that Armenia would not be fully independent for five years after the referendum, Moscow soon moved to change Armenia's course. Without notifying the Armenian government, Moscow sent paratroopers to the republic in early May, ostensibly to protect Soviet defense installations in Armenia. Ter-Petrosian's official statement in reaction characterized the move as a virtual declaration of war by the Soviet Union.

In August 1991, when a self-proclaimed emergency committee attempted to overthrow Gorbachev and take control in Moscow, the Armenian government refused to sanction its actions. Fearing an extension of the Soviet incursion of May, Ter-Petrosian approached the Moscow coup very cautiously. The republic's Defense Committee secretly resolved to have the Armenian armed forces go underground and wage guerrilla warfare. Ter-Petrosian, who believed that Gorbachev's personal blunders, indecisiveness, and concessions to conservative communists were to blame for the coup, was overjoyed when the conservatives were defeated. But the coup itself convinced Armenians of the need to move out of the Soviet Union as rapidly as possible, and it validated TerPetrosian 's refusal to participate in the revival of the Soviet Union advocated by Gorbachev.

Within two months of the coup, Armenians went to the polls twice. In September 1991, over 99 percent of voters approved the republic's commitment to independence. The immediate aftermath of that vote was the Armenian Supreme Soviet's declaration of full independence, on September 23, in disregard of the constitution's restraints on secession. Then in October, Ter-Petrosian was elected overwhelmingly as president of the republic. He now had a popular mandate to carry out his vision of Armenian independence and self-sufficiency.

As political changes occurred within the republic, armed conflict continued in Nagorno-Karabakh during 1991. Armenia officially denied supporting the "Nagorno-Karabakh defense forces" that were pushing Azerbaijani forces out of the region; Armenia also accused the Soviet Union of supporting Azerbaijan as punishment for Armenia's failure to sign Gorbachev's new Union Treaty. In turn, Azerbaijan called Armenia an aggressor state whose national policy included annexation of Azerbaijani territory.

Data as of March 1994