b. limiting nuclear arms
After dispatching Kissinger on a secret mission to make arrangements, Nixon traveled to Beijing in February 1972, becoming the first sitting U.S. president to visit the Chinese mainland. Protected by his long standing anti-communist credentials from political attacks at home, Nixon initiated diplomatic exchanges with the People's Republic of China and paved the way for Mao Zedong's government to join the United Nations.
By 1972, China, the United States, and the Soviet Union were each worried about the prospects of closer ties between the other two. Soviet premier Leonid Brezhnev responded to Nixon's China trip by inviting the president to Moscow, where the two leaders signed an arms limitation treaty, SALT I. Both sides agreed not to deploy any nuclear missiles exceeding existing levels and pledged further arms reduction talks. Nixon failed, however, to leverage this new relationship to end the Vietnam War.