The killing of General Suleimani is only the latest—and by no means unique—example of reliance on an A.U.M.F. long after its passage and far outside its reasonable scope.

Mr. Pence told Francis “you made me a hero” back home by granting him the private audience.

Trump’s appearance has also been met with criticism from some commentators.

In a separate proposed rule, the administration aims to protect the rights of religious student groups at public universities, giving them equal treatment with secular student groups.

Our prayers are with our country, all the members of the U.S. Senate and the president as this trial begins.

Despite the conceptual similarities, a Senate trial, formally referred to as a Court of Impeachment, is fundamentally different from a standard trial.