The overthrow of the monarchy in Afghanistan in 1973 was a seminal moment in the country's history and in U.S. policy in Central Asia. The return of Mohamed Daoud Khan to power was aided by the People's Democratic Party of Afghanistan (PDPA, the Communist party) and military officers trained in the Soviet Union. Even as Communism was making its first substantive gains in Afghanistan, the United States was wrestling with how best to pursue its strategy of containment. Stung by the experience of Vietnam, President Richard Nixon concluded that the United States could not unilaterally respond to every instance of Communist expansion. In the turbulent years that followed, U.S. diplomacy and Daoud's desire for nonalignment combined to mitigate Soviet influence in Afghanistan. However, the U.S. triumph was fleeting insofar as Daoud's shift toward nonalignment triggered the erosion of Soviet-Afghan relations, culminating in the overthrow of his government and the final ascension of the PDPA.