Chinese leader Xi Jinping brought up the issue of Taiwan Thursday during President Trump’s visit to China, warning that the “Taiwan question is the most important issue in China-U.S. relations.”“’Taiwan independence’ and cross-Strait peace are as irreconcilable as fire and water,” Xi said. “Safeguarding peace and stability across the Taiwan Strait is the biggest common denominator between China and the U.S.”The move doesn’t bode well for the U.S.-China summit, which Trump had said could be “the best summit ever.” The meeting between the two countries’ leaders is supposed to improve trade ties, with several U.S. executives making the trip with Trump.“Handled well, relations between the two countries can maintain overall stability,” Xi said. “If handled poorly, the two countries will collide or even clash, putting the entire U.S.-China relationship in an extremely dangerous situation.”Trump didn’t address questions from the press about Taiwan, only saying “Great. Great place. Incredible. China’s beautiful,” after his morning conversation with Xi. The White House’s readout of the meeting didn’t even mention Taiwan.“President Trump had a good meeting with President Xi of China,” a White House official said. “The two sides discussed ways to enhance economic cooperation between our two countries, including expanding market access for American businesses into China and increasing Chinese investment into our industries. Leaders from many of the United States’ largest companies joined a portion of the meeting.”This suggests that the Trump administration is taking the issue seriously. In December, the U.S. reached an $11 billion arms deal with Taiwan, which was condemned by China, which has never ruled out invading the island. The majority of Taiwan’s people want things to stay the way they are: neither declaring independence from China nor submitting to Chinese authority. If Xi decides to push reunification, what would Trump do?