in March 2006 for the "trilateral security forum" with the Japanese foreign minister Taro Aso and his Australian counterpart Alexander Downer. US–Japan–Australia–India (the "Quad") In May 2007, the four nations signed a strategic military partnership agreement, the Quadrilateral Security Dialogue. US–Japan–India The three nations held their first trilateral meeting in December 2011. US–Taiwan (ROC) Although the United States recognized the People's Republic of China in 1979, the US maintains de facto diplomatic relations and is bound to it by the Taiwan Relations Act, which ambiguously states, "the United States will make available to Taiwan such defense articles and defense services in such quantity as may be necessary to enable Taiwan to maintain a sufficient self-defense capabilities". Previously, the United States recognized the Republic of China as the sole legitimate government of China despite the loss of the territory during the Chinese Civil War. In 1954, the US and the ROC on Taiwan (Formosa) signed the Sino-American Mutual Defense Treaty, which essentially prevented the People's Liberation Army from taking over the island of Taiwan. During the Cold War, the treaty prolonged and assisted the Republic of China in maintaining legitimacy as the sole government of the whole of mainland China until the early 1970s and also helped US policymakers to shape the policy of containment in East Asia together with South Korea and Japan against the spread of communism. In 1980, the treaty was abrogated after the US normalized relations with the PRC. The recent decade has seen an increasing frequency of US arms sales to Taiwan alongside expanding commercial ties. On December 16, 2015, the Obama administration announced a deal to sell $1.83 billion worth of arms to the Armed Forces of Taiwan, a year and eight months after U.S. Congress passed the Taiwan Relations Act Affirmation and Naval Vessel Transfer Act of 2014 to allow the sale of Oliver Hazard Perry-class frigates to Taiwan. The deal would include the sale of two decommissioned U.S. Navy frigates, anti-tank missiles, Assault Amphibious Vehicles, and FIM-92 Stinger surface-to-air missiles, amid the territorial disputes in the South China Sea. A new $250 million compound for the American Institute in Taiwan was unveiled in June 2018, accompanied by a "low-key" American delegation. The Chinese authorities denounced this action as violation of the "one China" policy statement and demanded the US to stop all relations with Taiwan without intercession of China. In 2019, the US