"The ultimate beneficiary of Nixon’s summitry was Leonid Brezhnev. The Soviet party leader had staked his bid for outright leadership on a policy of peaceful coexistence with the United States. That made sense for economic and defense reasons, not to mention the looming threat from China. In the spring of 1972 Brezhnev let nothing, not even the American mining of North Vietnam, get in the way of a summit. The arms control agreements signed in Moscow in May silenced his critics and apparently confirmed the Soviet Union’s equality with the United States. The statement of Basic Principles also suggested that the Americans were accepting détente on Soviet terms. Had Nixon remained potent in the second term he might have held the Kremlin to account, as he believed had not been done after Yalta. Instead his crumbling presidency gave the Soviets and their allies an increasingly free hand to act as they pleased. By the middle of 1975 communist forces controlled all of Indochina. Over the next few years the Soviets extended their influence in eastern and southern Africa, in ways that fitted their understanding of détente— a world made safe for class struggle—but also undermined support for the process in the United States. In 1976 Gerald Ford, Nixon’s successor, banned the word “détente” from the official diplomatic lexicon. Nixon’s failure, in other words, relegated not merely summitry but diplomacy to the back burner. Dialogue with Moscow atrophied. And after the Brezhnev Politburo sent troops into Afghanistan at the end of 1979, Soviet-American relations degenerated into what was dubbed a “new cold war.”"