For decades, a carefully maintained ambiguity has kept the peace across the Taiwan Strait — but that equilibrium now rests in the hands of a president who has little patience for ambiguity. As Donald Trump prepares to engage Xi Jinping, allied nations from Tokyo to Canberra are confronting a disquieting possibility: that Taiwan's security, long treated as a principle, could be reframed as a price. What is at stake is not only the island's future, but the credibility of every promise America has ever made to a smaller nation counting on its protection.