By late 1962, opposition to Khrushchev’s reformist policies had gained momentum in party circles. Khrushchev’s Communist colleagues began to see de-Stalinization as a dangerous threat to the authority of the party. Moreover, Khrushchev’s policy toward the West was erratic and ultimately unsuccessful. In 1958, Khrushchev tightened border controls between East and West Berlin and ordered the Western allies to evacuate the city within six months. In response, the allies reaffirmed their unity in West Berlin, and Khrushchev backed down. Then, with Khrushchev’s backing, the East German authorities built a wall between East and West Berlin in 1961, sealing off West Berlin, in clear violation of existing access agreements among the Great Powers. The recently elected U.S. president, John F. Kennedy (r. 1961–1963), privately hoping that the wall would lessen Cold War tensions by easing hostilities in Berlin, did little to prevent its construction.

Emboldened by American acceptance of the Berlin Wall and seeing a chance to change the balance of military power decisively, Premier Khrushchev secretly ordered missiles with nuclear warheads installed in Fidel Castro’s Communist Cuba in 1962. When U.S. intelligence discovered missile sites under construction, Kennedy countered with a naval blockade of Cuba. After a tense diplomatic crisis, Khrushchev agreed to remove the Soviet missiles in return for American pledges not to disturb Castro’s regime. In a secret agreement, Kennedy also promised to remove U.S. nuclear missiles from Turkey.

Khrushchev’s influence declined rapidly after the Cuban missile crisis. In 1964, the reformist premier was displaced in a bloodless coup, and he spent the rest of his life under house arrest. Under his successor, Leonid Brezhnev (1906–1982), the U.S.S.R. began a period of limited re-Stalinization and economic stagnation. Soviet leaders, determined never to suffer Khrushchev’s humiliation in the face of American nuclear superiority, launched a massive arms buildup. Yet Brezhnev proceeded cautiously in the mid-1960s and avoided direct confrontation with the United States.

Despite popular protests and changes in leadership, the U.S.S.R. and its satellite countries had achieved some stability by the late 1950s. East and West traded propaganda threats, but both sides basically accepted the division of Europe into spheres of influence. Violent conflicts now took place in the developing world, where decolonization was opening new paths for Cold War confrontation.