Protection of human rights became one of the major foreign policy goals of the next U.S. president, Jimmy Carter (b. 1924). Ironically, just at the point when U.S. involve Protection of human rights became one of the major foreign policy goals of the next U.S. president, Jimmy Carter (b. 1924). Ironically, just at the point when U.S. involvement in Vietnam came to an end and relations with China began to improve, the mood in U.S.-Soviet relations began to sour, for several reasons. Some Americans had become increasingly concerned about aggressive new tendencies in Soviet foreign policy. The first indication came in Africa. Soviet influence was on the rise in Somalia, across the Red Sea in South Yemen, and later in Ethiopia. Soviet involvement was also on the increase in southern Africa, where an insurgent movement supported by Cuban troops came to power in Angola, once a colony of Portugal. Then, in 1979, Soviet troops were sent to neighboring Afghanistan to protect a newly installed Marxist regime facing rising internal resistance from fundamentalist Muslims. Some observers suspected that the Soviet advance into hitherto neutral Afghanistan was to extend Soviet power into the oil fields of the Persian Gulf. To deter such a possibility, the White House promulgated the Carter Doctrine, which stated that the United States would use its military power, if necessary, to safeguard Western access to the oil reserves in the Middle East. In fact, sources in Moscow later disclosed that the Soviet advance into Afghanistan had little to do with a strategic drive toward the Persian Gulf but represented an effort to take advantage of the recent disarray in U.S. foreign policy in the aftermath of defeat in Vietnam to increase Soviet influence in a sensitive region increasingly beset with Islamic fervor. Soviet officials feared that the wave of Islamic activism could spread to the Muslim populations in the Soviet republics in central Asia and were confident that the United States was too distracted by the “Vietnam syndrome” (the public fear of U.S. involvement in another Vietnam-type conflict) to respond. Other factors contributed to the growing suspicion of the Soviet Union in the United States. During the era of détente, Washington officials had assumed that Moscow accepted the U.S. doctrine of equivalence—the idea that both sides possessed sufficient strength to destroy the other in the event of a surprise attack. By the end of the decade, however, some U.S. defense analysts began to charge that the Soviets were seeking strategic superiority in nuclear weapons and argued for a substantial increase in U.S. defense spending. Such charges, combined with evidence of Soviet efforts in Africa and the Middle East and reports of the persecution of Jews and dissidents in the Soviet Union, helped undermine public support for détente in the United States. These changing attitudes were reflected in the failure of the Carter administration to obtain congressional approval of a new arms limitation agreement (SALT II) signed with the Soviet Union in 1979.