As Democrats in the House of Representatives edge closer to impeaching Donald Trump, the president and his supporters roar in dismay and outrage. Impeachment is nothing less than an attempted coup d'etat, they argue over and over. It amounts to an assault, writes Tucker Carlson, on the “fundamental cornerstone” of American democracy: “respect[ing] the will of the voters.” Peter Navarro, the White House trade adviser, describes the House impeachment inquiry as “an end run around the ballot box.” In a piece for The Hill, Trump ally Jenna Ellis Rives warns that all Americans should be appalled by the Democrats’ bid “to undermine a free and fair election.”

If you’re not a Republican or a Trump fan, these perfervid denunciations of impeachment as illegitimate and antidemocratic may strike you as unhinged. After all, the power to impeach and remove a president is specified in the Constitution. It has been there — in Article II, Section 4 — for 230 years. House Speaker Nancy Pelosi and Judiciary Committee Chairman Jerrold Nadler have not proposed to do anything illegal or capricious. The GOP’s angry accusation that impeachment subverts America’s constitutional norms, Democrats must be thinking, just goes to show how poorly the GOP understands those norms.

Yet when the impeachment shoe was on the other foot, it was Democrats who lined up to condemn the use of a constitutional tool as an illicit insurrection. The same “coup” language used so promiscuously by overwrought defenders of Trump today was used just as loosely by agitated backers of Bill Clinton then.

“This partisan coup d'etat will go down in infamy in the history of this nation,” thundered Nadler in 1998, as the House of Representatives — then led by a Republican majority — debated whether to impeach the 42nd president. Ed Markey, who at the time represented Massachusetts’ 7th congressional district, was just as appalled: “We are now on the threshold of overturning the people’s choice for President,” he said. “We are permitting a constitutional coup d'etat which will haunt this body forever.”

Joe Biden, Charles Schumer, Nancy Pelosi, Maxine Waters, Bernie Sanders — all of them made the exact same argument against the impeachment of a Democratic president that Team Trump is making against the impeachment of a Republican: that only the voters should decide who sits in the Oval Office, and anything that overrides their will is tantamount to mutiny.

But you don’t have to go back 20 years to find throngs of liberals and Democrats bitterly disparaging a venerable constitutional process as an illegitimate violation of American democracy. Just see how they rail against the Electoral College.

Like impeachment, the Electoral College has been a part of the Constitution for more than two centuries. Electoral College calculations have been integral to every presidential campaign since John Adams ran for reelection. In 2016, neither Trump nor Hillary Clinton focused on winning the popular tally; each candidate’s goal was to amass 270 electoral votes.

Yet Trump’s victory triggered an avalanche of anti-Electoral College resentment that still hasn’t subsided. Trump opponents blast the system as “undemocratic” and “a threat to democracy.” They question the “legitimacy” of Trump’s election, on the grounds that he “squeaked into office on an Electoral College technicality.” They charge the Electoral College with “routinely” perverting American self-government by producing outcomes “where the will of the voters is thwarted.”

In the runup to the 2016 election, when Clinton was expected to win, Trump refused to say that he would accept the outcome of the vote — a position the Democratic standard-bearer called “horrifying.” Once it became clear that Trump had prevailed, however, the chorus flipped 180 degrees, decrying the injustice of the Electoral College, and suggesting at every turn that a president who lost the popular vote was by definition a president who lacked validity.

All of this — raging against impeachment as a “coup,” denying the authority of a clear Electoral College majority — are manifestations of the tribalism ripping apart the seams of our civic fabric. To be sure, in politics there is always a temptation to insist that my side must be right, and yours must be wrong. But political partisanship has grown so extreme that it now leads partisans to denigrate even the validity of constitutional tools that were in place before the Republican and Democratic parties even existed.

This is dangerous. Impeachment and the Electoral College are elements of our constitutional architecture. They were incorporated in the nation’s basic legal charter by framers convinced of their utility to the machinery of American self-government. They aren’t liberal or conservative. They aren’t the weapon of one party or the other. And the results they produce are not illicit or traitorous.

Emotions run high. Our battles are passionate. But the Constitution’s provisions belong to us all, even in the heat of argument. If we can no longer agree even on that, we are in more trouble than we realize.

(Jeff Jacoby is a columnist for The Boston Globe).