In April of 1978, the People's Democratic Party of Afghanistan (PDPA) backed by Soviet military advisors, led a coup that has become known as the Saur Revolution. They overthrew a group of Islamist reformers that controlled the country from Kabul, and once in power, they PDPA instituted a series of communist-style reforms that were intended to reorganize traditional Afghan farming and bring about the modernization of the state. These reforms were never popular with the Afghan people, however, and even some supporters were uncomfortable with the involvement of the Soviets.
Mohammad Taraki, the new government leader, failed to maintain control, and the PDPA fractured into several factions, each led by government officials. One of these officials, party secretary Amin, had Taraki murdered, a move that infuriated Soviet premier Leonid Brezhnev, who hoped to unify the party under Soviet influence.
Brezhnev was also concerned with Amin's inability to deal with the mujahideen, a growing resistance movement in Afghanistan that was gaining in momentum and even attracting foreign fighters. Brezhnev decided to intervene by sending in a contingent of over 100,000 Soviet troops in December of 1979. The soldiers executed Amin and installed his rival in the PDPA, Babrak Kamal, as president. This move, however, only caused matters to deteriorate further, as the mujahideen interpreted Soviet actions as an invasion, and launched a massive resistance campaign.
Meanwhile, Amin failed to secure the support of the Afghan people, many of whom joined the resistance movement, and the Soviets were forced to import large quantities of grain to feed people in the face of a large famine. In addition, the move sparked international outrage, especially from the United States, who withdrew from the Summer Olympics and planned arms limitation talks in protest. The Soviets were dragged into a long, bloody conflict that would lead to widespread disillusionment and weaken the authority of the Communist Party.