<noinclude> The United States foreign policy toward the People's Republic of China originated during the Cold War. At that time, the U.S. had a containment policy against communist states. The leaked Pentagon Papers indicated the efforts by the U.S. to contain China through military actions undertaken in the Vietnam War. The containment policy at East Asian island arcs is called "the First and Second island chains". President Richard Nixon's China rapprochement signaled a shift in focus to gain leverage in containing the Soviet Union. Formal diplomatic ties between the U.S. and China were established in 1979, and with normalized trade relations since 2000, the U.S. and China have been linked by closer economic ties and more cordial relations. During the 2010s and early 2020s, there was a significant shift in America's China policy. In his first term as U.S. president, Barack Obama said, "We want China to succeed and prosper. It's good for the United States if China continues on the path of development that it's on." The Trump administration stated, "The United States recognizes the long-term strategic competition between our two systems." The Biden administration stated that previous optimistic approaches to China were flawed, and that China poses "the most significant challenge of any nation-state in the world to the United States". However, the US National Security Advisor, Jake Sullivan, has stated that the Biden administration does not pursue a fundamental transformation of the Chinese political system. U.S. military presence in the region, efforts to improve relations with India and Vietnam, and the Obama administration's 2012 "Pivot to Asia" strategy for increased American involvement in the Western Pacific, have been associated with a policy aimed at countering China's growing clout. The Trump administration designated China as a "revisionist power" seeking to overturn the liberal international order and displace the United States, and called for a whole-of-government approach to China guided by a return to principled realism. Current U.S. military presence in the region includes military alliances with South Korea, with Japan, and with the Philippines. Strategic background Cold War era During the Cold War the United States tried to prevent the domino theory of the spread of communism and thwart communist countries including the People's Republic of China. Washington assumed that Communist North Vietnam would be a puppet state of China. However those two later went to war. Post-Cold War In more contemporary times, with the Nixon rapprochement and