Under the longstanding doctrine of strategic ambiguity, the US government has deliberately refused to state in advance whether it would send forces to defend Taiwan in the event of a Chinese attack. That calculated silence has been the cornerstone of cross-strait deterrence since the 1970s, allowing Washington to maintain ties with Beijing while reassuring Taipei.
But that ambiguity is being aggressively tested. In a September 14 analysis in Foreign Policy, columnist James Crabtree declared that “Trump is killing ‘strategic ambiguity’ over Taiwan,” pointing to “signals from Washington” that the United States is “inching more toward a position of nonintervention.” Geopolitical risk analyst Shahn Louis has likewise said “the era” of strategic ambiguity “is over.” Michael Schiffer, a former US deputy assistant secretary of defense for East Asia, argued it is “no longer a sustainable or effective policy.”
The erosion is visible in Taiwanese public opinion. Multiple polls show the belief among Taiwan’s people that the United States would come to their defence has decreased since 2025. The reasons, analysts say, are not hard to find: President Trump has repeatedly made four points about Taiwan that call into question the reliability of American commitments.
Yet despite these alarm bells, the article’s author, Denny Roy, contends that strategic ambiguity is far from finished. The policy’s fundamental logic—keeping China guessing and Taiwan dependent on US support—remains intact, even if its credibility has taken a hit. The question is whether Washington can repair the damage before Beijing tests the resolve it doubts.