Upon taking office in 1968, President Richard Nixon, assisted by his National Security Advisor Henry Kissinger, sought ways to improve relations with the Soviet Union and reduce tension. His policy of "détente" (French for "relaxation") utilized trade and arms agreements to find common ground with the Soviet Union. Nixon increased trade to the Soviet Union, helping to improve their economy. In addition, he negotiated the SALT I and Anti-Ballistic Missile treaties. These were arms control treaties, designed to put limits on the number of nuclear weapon launchers each side could have and forbid the creation of missile shields. Nixon also normalized relations with communist China, in an effort to strengthen the U.S. position in East Asia. The policy of Détente would continue under President's Gerald Ford and Jimmy Carter, ending with the Soviet invasion of Afghanistan in 1979.