Even before the American Revolution, colonial politicians had begun resuscitating the idea of impeachment, a 14th-century English legal concept that had become moribund. John Adams argued even before the war that impeachment was a fundamental right of British subjects. The problem with a monarchy, after all, was that the people couldn’t revoke consent to be governed by him or, occasionally, her. The revolution was a way of putting that into practice.

“The famous ‘shot heard around the world’ was a gun, but the initial shots heard round the world were impeachments by the American democratically elected legislators of followers of the crown who were executing the orders of the crown,” Sunstein said.

But the formulation in the U.S. Constitution—providing for impeachment in the case of “treason, bribery, or other high crimes and misdemeanors”—is the somewhat opaque product of a debate in the Constitutional Convention. Alexander Hamilton’s successful advocacy for a unitary executive produced a backlash among delegates who feared the creation of a new monarch. Impeachment was the essential safety valve.

How to structure it, though? Roger Sherman’s suggestion of a Senate that could impeach a president for any reason was rejected for making the presidency too precarious. A counterproposal allowing for impeachment in cases of “maladministration” was found to be too vague. There’s no record of further discussion of the final terms at the convention, but in the Federalist Papers, Hamilton offered some clarification, writing that impeachable offenses were those that concerned “the abuse or violation of some public trust. They are of a nature which may with peculiar propriety be denominated political, as they relate chiefly to injuries done immediately to society itself.”

That’s central, Sunstein said, because it makes clear two important points about when impeachment is proper: First, it need not require an actual crime; and second, it is primarily about gross neglect or abuse of power. If that is true, the complaints, sometimes voiced by pearl-clutching pundits, that impeachment might be “politicized” seems almost laughable. But it also means that much of the (very early) debate about impeaching Trump is fought on questionable grounds.

“[House Minority Leader Nancy] Pelosi made a terrible blunder in saying relatively recently that the question is whether the president has committed a crime,” Sunstein said. “That is not the question.”

It also means that of the several articles of impeachment brought or nearly brought against American presidents, most of them fail to meet the Founders’ test. Andrew Johnson was impeached for firing Cabinet members, a move that violated an act of Congress that Johnson sincerely (and correctly) believed was an unconstitutional infringement on the separation of powers. Even if he had been wrong, Sunstein said, Johnson should not have been impeached for a good faith move.