Taiwan’s doubts about America are growing. That could be dangerous.

The collection of American memorabilia, vast and well-lit in a busy area of City Hall in the southern Taiwanese city of Tainan, reflected decades of eager courtship. Maps highlighted sister cities in Ohio and Arizona.

There was a celebration of baseball, an American flag laid out on a table. And in the middle of it all, a card sent to the United States that seemed to reveal the thinking of Tainan, a metropolis of 1.8 million, and nearly all of Taiwan.

“Together, stronger,” it said. “Solidarity conquers all.”