One-China policy
By the 2010s, the U.S. had recognized the PRC's China as the one and only China for decades. However, when Donald J. Trump won the U.S. presidential election in 2016, Trump broke the U.S. code of conduct towards China when he spoke with Taiwanese President Tsai Ing-wen in a telephone call. This rose questions over the U.S.' commitment to its One-China policy. President Trump attempted to alleviate these doubts during a call on February 9, 2017 with China's paramount leader Xi Jinping, in which he restated he would honor the One China policy. Despite honoring this policy, the U.S. still maintains unofficial ties with Taiwan, including the provisions of defense aid.