Impeachment Battle to Turn for First Time on a President’s Ties to a Foreign Country

“There was a concern, even a paranoia, about foreign intervention, about people who don’t have the interests of a new country being taken advantage of by an old power,” said Corey Brettschneider, a political-science professor and constitutional scholar at Brown University and author of “The Oath and the Office.”

The framers expressed this explicitly by inserting what is now called the emoluments clause in the Constitution, barring international payments or gifts to a president or other federal elected official: “No person holding any office of profit or trust under them, shall, without the consent of the Congress, accept of any present, emolument, office, or title, of any kind whatever, from any king, prince, or foreign state.”

Once a forgotten element of the Constitution, it has attained new popular recognition in the Trump era as multiple critics of the president wage legal battles arguing that he has violated the emoluments clause through hotels and resorts of his that are patronized by Middle East sheikhs and other foreign potentates.

Indeed, Mr. Trump’s entire presidency has been shadowed by questions of foreign ties. The special counsel, Robert S. Mueller III, concluded his investigation by saying he had not found sufficient evidence to establish a criminal conspiracy between Russia and Mr. Trump’s 2016 presidential campaign, but that was a narrow legal judgment.

While the president has sought to interpret that report to mean that Russia’s ties to the campaign were a “hoax” made up by his opponents, in fact Mr. Mueller’s investigation documented extensive contacts between Mr. Trump’s associates and Russian figures.

It concluded that the Kremlin sought specifically to help Mr. Trump get elected, and Mr. Mueller said Mr. Trump’s campaign welcomed Russia’s help. Mr. Trump at one point even publicly called on Russia to find Hillary Clinton’s missing emails, and within hours Russian agents sought to do just that by trying to break into her computer servers.

In the end, House Democrats shied away from trying to impeach Mr. Trump on those grounds since Mr. Mueller said he could not establish a criminal conspiracy. But it set the stage for the current impeachment battle.