Americans often boast that we are a nation of laws, but for the moment laws appear to play a decidedly secondary role in the drama we are living in and—hopefully—through.

We have some guidance from our foundational law, the Constitution, which tells us how to proceed: the House of Representatives has “the sole power of impeachment,” the Senate has “the sole power to try all impeachments,” and must do so “on oath or affirmation.” The Senate cannot convict “without the concurrence of two-thirds of the members present.” And “when the president of the United States is tried, the chief justice shall preside.”

It looks almost like a real trial. Yet despite the legal trappings, the underlying standard, if applied to a criminal statute, would be vulnerable to attack as void for vagueness: “The president . . . shall be removed from office on impeachment for, and conviction of, treason, bribery, or other high crimes and misdemeanors.” Treason and bribery have specific and recognized meanings, but what about “other high crimes and misdemeanors”?

In Federalist No. 66, Alexander Hamilton defended the Senate as the tribunal for trying impeachments in part by saying that impeachable offenses come from “the abuse or violation of some public trust” and “are of a nature which may . . . be denominated political.”

Tellingly, during President Clinton’s impeachment trial, Chief Justice William Rehnquist was asked to instruct senators, as judges uniformly instruct jurors, that in reaching a verdict they must consider only the evidence presented during the trial. He refused; senators were free to consider whatever they wished. In fact, they were free to consider nothing; the Constitution imposes on the Senate no obligation to hold a trial at all. President Andrew Johnson was impeached on 11 charges, but tried on only three. As for the House, the only governing principle there is that the majority rules.