Li Zhao, one of the labor activists who went missing over the weekend, is seen here in Nanzhang county, Xianyang city, in central China's Hubei province in March 2016. (Deng Guilian via Associated Press)

IVANKA TRUMP’S conflicts of interest as a White House adviser already included the dependence of her clothing brand on Chinese manufacturers even as she and her husband participate in White House meetings with senior Chinese officials. Now a new and more troubling connection has come up: Authorities have moved to silence labor activists who were documenting poor working conditions at the factories that make Ivanka Trump shoes.

According to China Labor Watch, a U.S.-based advocacy organization, one of its investigators has been arrested and two others have disappeared after they probed working conditions at two factories of Huajian International, a shoe manufacturer that produces about 100,000 pairs a year for the Ivanka Trump brand. An interim report issued by the nongovernmental organization last month said it had documented working shifts as long as 18 hours and pay that in some cases was less than the equivalent of $1 an hour.

One of the investigators, Hua Haifeng, was prevented from traveling to Hong Kong last week to meet with China Labor Watch representatives and journalists. His wife said she received a phone call on Monday saying he had been detained on a charge of “illegal monitoring.” The other two activists, Li Zhao and Su Heng, also disappeared over the weekend.

No doubt Ms. Trump, who has turned over management over her clothing line to others, had nothing to do with this crackdown. But the founder of China Labor Watch told The Post’s Simon Denyer that he thinks authorities acted because of the factories’ connection to Ms. Trump. In 17 years of monitoring factories — including firms producing goods for Apple and Samsung — his investigators had never before been arrested.

Ms. Trump may suppose that her recusal from her company — she retains her ownership interest — means she is immune from favors from foreign governments seeking advantage inside the White House. But the regime of Xi Jinping doesn’t seem to see it that way. On the same day that Ms. Trump helped to host Mr. Xi at the Mar-a-Lago estate, China’s patent office granted her company a number of trademarks. Now the regime is trying to stifle embarrassing reports about how her company, far from heeding President Trump’s exhortation to “hire American,” is depending on the crude exploitation of Chinese workers.

Huajian, by the way, is not the only Trump contractor in China caught abusing its employees. The Post’s Drew Harwell reported in April that a factory used by the G-III Apparel Group, which makes dresses, blouses and other clothes for the Ivanka Trump brand, keeps workers on the line for nearly 60 hours a week for wages of little more than $62. Since the presidential election, sales of Ms. Trump’s clothes have reportedly soared, so there likely will be plenty more of such work in China and other Asian sweatshops; don’t expect Mr. Trump’s promise to return manufacturing jobs to the United States to be applied to his own family.

Ms. Trump has two ways to avoid being the beneficiary of unseemly favors — wanted or unwanted — from Mr. Xi’s regime. She can recuse herself from all government business involving China and all other countries where her clothes are made; or she can divest her interest in her company. If she does neither, it will be reasonable to ask whether sweatshop labor and political repression are now part of the fabric of U.S.-China relations.