Some human rights issues draw greater bipartisan support than others. China hawks have become ascendant across Congress and in the administration, and many Americans increasingly see China as a threat.

Although Vice President Mike Pence and Secretary of State Mike Pompeo have criticized China on the persecution of Muslims, Mr. Trump has said nothing. In July, Jewher Ilham, the daughter of Ilham Tohti, a Uighur professor whom China sentenced to life in prison in 2014, joined other victims of religious persecution to meet with Mr. Trump in the Oval Office. When she tried to explain the camps to Mr. Trump, he appeared ignorant of the situation and simply said, “That’s tough stuff.”

“It’s hard to find evidence of genuine personal interest,” said Sophie Richardson, China director at Human Rights Watch. “On China, at a minimum, President Trump should stop describing an authoritarian, abusive leader as a ‘terrific guy’; doing so gives Chinese authorities the opportunity to choose between that characterization and the far tougher ones offered up by other senior U.S. officials.”

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Mr. Trump, who has criticized China over its economic practices, has refrained from imposing sanctions on Chinese officials responsible for the camps for fear of jeopardizing the chances of reaching a trade deal. Many top aides and lawmakers from both parties have pushed for sanctions, but the Treasury Department has opposed the penalties. The Uighur act, which had Mr. Rubio and Representative Christopher H. Smith, Republican of New Jersey, as sponsors, would compel Mr. Trump to impose sanctions on Chen Quanguo, the top Communist Party official in Xinjiang, where the camps are.

In October, the Trump administration placed a few Chinese businesses and security organizations on a commercial blacklist because of their suspected roles in Muslim abuses, but many analysts considered that a weak punishment.

Other countries are more complicated. Saudi Arabia has been a traditional American ally, and Iran hawks in Congress, who are generally Republican, argue Riyadh is a regional bulwark against Tehran. And Mr. Trump’s positive declarations about President Vladimir V. Putin of Russia have spurred a gradual shift from the anti-Russia views previously held by Republican politicians, conservative voters and right-wing news organizations.