Amid the dizzying details of internet trolls, almost a million dollars’ worth of antique rugs and fake bank accounts, the indictments brought by Robert Mueller, the special counsel, in his investigation of Russian tampering in the 2016 election have one thing in common.

Both the indictment of 13 Russians associated with a troll farm called Internet Research Agency and the indictment of President Trump’s onetime campaign chairman Paul Manafort accuse the defendants of pretending to engage in American politics in good faith but secretly serving someone else’s interest. In both cases, the charge, “conspiracy to defraud the United States,” is an assertion that they were really serving the interests of Russia or of a Russian-backed Ukrainian politician, and that by hiding their true intent, the defendants prevented the United States government from protecting our politics from undisclosed outside influence.

That precedent, and the guilty plea to the same charge by Rick Gates, Mr. Manafort’s deputy, may pose a real danger to Jared Kushner, the president’s son-in-law and senior adviser. According to reports, Mr. Mueller appears to be assessing whether Mr. Kushner, in the guise of pursuing foreign policy on behalf of the United States, was actually serving the interests of his family and foreign governments.

On Tuesday, The Washington Post reported that “officials in at least four countries” — United Arab Emirates, China, Israel and Mexico — “have privately discussed ways they can manipulate” Mr. Kushner by taking advantage of his “complex business arrangements, financial difficulties and lack of foreign policy experience.” The president gave his son-in-law an expansive foreign policy role, including an effort to negotiate peace between Israel and the Palestinians. The implication in the article is that the United States government has intercepted communications of foreign leaders talking about ways they could take advantage of Mr. Kushner, whose family real estate empire is facing substantial debt woes.