Soon after Russia invaded Ukraine, Taiwan’s leaders joined the United States and its allies in declaring solidarity with the victim. Taiwan and Ukraine were fellow democracies, they said, each imperiled by its hulking, authoritarian neighbor.

       Now, President Trump’s turn against Ukraine could fan debate in Taiwan about whether it can count on American support in the event of a widening conflict with China, which claims the self-governed island as its territory.

       “Taiwan spent the better part of the past three years making the case for how the fate of democracies is intimately tied and what happens to Ukraine affects Taiwan,” said Russell Hsiao, the executive director of the Global Taiwan Institute, which is based in Washington.

       “With the seemingly abrupt change in the U.S. position on the Ukraine war,” Mr. Hsiao said, “this could have the effect of causing some in Taiwan to question whether the United States could pull the rug from underneath them.”

       Advertisement

       SKIP ADVERTISEMENT

       For decades, Taiwan has faced the possibility of invasion by China, which now sends fighter jets and warships nearly every day to probe its defenses. Taiwan’s ability to deter a potential attack hinges on whether the United States stands ready to help and even send forces. The island’s leaders have made closer ties with Washington a pillar of its foreign and defense policy for nearly a decade.

       But as Mr. Trump executes a dramatic reversal of U.S. policy toward Ukraine, abandoning Western efforts to punish Russia for the invasion and insisting that Ukraine is to blame for the war, the United States’ partners, including Taiwan, are being forced to assess their own positions and weigh how to secure Mr. Trump’s support.

       Subscribe to The Times to read as many articles as you like.