Nothing worried the framers more when the Constitution was being cast into shape than impeachment. In fact, the issue was never quite settled, and that’s why we find ourselves where we find ourselves this morning as the impeachment trial against President Trump begins in the Senate.

What loomed over the framers was the example of England, where the House of Commons asserted itself by the Bill of Attainder, or the legislative condemnation, of Thomas Wentworth, 1st Earl of Strafford, King Charles I’s first minister. The House declared Wentworth politically obnoxious and, without any trial, cut off his head. A long period of civil war followed. In the end, this principle was established: Governments rule only so long as they command “the confidence of the House.” The term for this doctrine is parliamentary sovereignty.

The American Revolution was led by the colonial gentry against the sovereignty of the Westminster Parliament. The republic they founded was not to be parliamentary: Elaborate checks and balances were meant to keep Congress, as much as the president, from monopolizing power. The Constitution explicitly forbade attainders and established a finicky system, impeachment, for removing delinquent officers.

Two of the cleverest and gloomiest of the Federalist Papers try to moderate “the vehemence” with which impeachment “is assailed.” Alexander Hamilton was under no illusions. Impeachment will often be not legal but “political.” The decision will be regulated "more by the strength of parties than by innocence or guilt.” Welcome to 2020.

But the curious thing is this: Although the public likes to think the republic runs on the fixed letter of the Constitution, it actually runs on convention and inhibition. The legislature has often been opposed to the executive and the judiciary; yet, by convention and nothing else, it’s still been extremely reluctant to use the ultimate weapon of impeachment. In 231 years, only 23 people have had their impeachment reach committee stage and, in 16 cases, it was as corrupt, treacherous, lascivious, or drunken scoundrels.

That leaves seven cases.

What’s constant to the seven is that, in revolutionary moments and only then, Congress can cease to regard the White House or Supreme Court as legitimate and shed its usual restraint about ideological impeachment.

In what it liked to call the “Revolution of 1800,” the Jeffersonian Left won power from George Washington’s conservative Federalists and set about purging the judiciary. Justice Samuel Chase of the Supreme Court was impeached essentially for the crime of not being Jeffersonian.

Again, in 1859, the new Republican Party, furiously anti-slavery, became dominant in the House. It abhorred President James Buchanan. A few years later, after the murder of President Abraham Lincoln, Republicans, as Henry James remembered, “recoiled in dismay from the sight of Mr. Andrew Johnson perched on the stricken scene. We were to have it in our eyes for three or four years!” In both cases, the Republicans progressed from horror to impeachment.

The cultural revolution of the 1960s divided America bitterly. Gerald Ford, leader of the House Republicans, tried to impeach Justice William Douglas with himself as the chief witness. The charge was, essentially, hippiedom: “Wild Bill” was a defender of “left-wing folk-singers” of the “lusty, lurid, and risque,” and the Swedish pornography film I am Curious (Yellow).

The counterblast came a few years later. The hysterical loathing cultural liberals felt and feel for President Richard Nixon inspired them to try to remove him over the Watergate scandal.

The GOP, in what it liked to call the “Revolution of 1994,” took the House after 40 years in opposition. Regarding President Bill Clinton as illegitimate, it went looking for grounds to impeach: If Arkansas land deals wouldn’t suffice, sexual romps and scandalous affairs might.

A fourth revolutionary moment came in 2016. The populist Trump took over a hostile Republican Party, then won the election. Some Democrats began talking of impeachment before he was even inaugurated. The wonder is that it took them so long — now, the belated effort has the air of an election-year stunt.

Ideological impeachment is a symptom. It’s revulsion that makes it possible.

Those on the Left who hold the Ukraine caper to be an outrageous crime and those of us on the traditionalist Right who agree should not delude ourselves. The present action is underway because we never accepted Trump as legitimate. Constitutional machinery is being used in an extraconstitutional spirit.

The question is how long this revolutionary moment will last.

Trump will survive his trial and probably win reelection. A Democratic House will probably try again. Or, say Trump loses, the Republican Party remains Trumpian, and it wins the 2022 midterm elections: Won’t it immediately contemplate impeaching a President Joe Biden?

And so on. The frivolous impeachment of Clinton and the doomed impeachment of Trump have cheapened the extreme remedy. As long as we remain as divided as we are, we’ll keep using it and abusing it. The foreboding of Hamilton will come to pass: Each impeachment “will agitate the whole community and divide it into parties friendly or inimical to the accused. It will connect itself with the preexisting factions and will enlist all their animosities.”

This isn’t a cheery prospect.

Richard Major is a novelist living in Virginia. His eighth novel, Piracies, will be published next week. His website is www.RichardMajor.com.