WASHINGTON: Whether by accident or design, President-elect Donald Trump is signaling a tougher American policy towards China, sparking warnings from both the outgoing Obama administration and Beijing. On Monday, White House spokesman Josh Earnest said progress with the Chinese could be "undermined" by a flare-up over the sovereignty of Taiwan, the self-governing island the US broke diplomatic ties with in 1979. That split was part of an agreement with China, which claims the island as its own territory, although the US continues to sell Taiwan billions in military equipment and has other economic ties. Trump broke protocol last week by speaking with Taiwanese President Tsai Ing-wen, and then...