Donald Trump's repeated and unfounded claims that the election will be rigged against him has a lot of commentators worried. "Trump is nonchalantly taking a sledgehammer to the bedrock of the American government," Dara Lind at Vox.com writes. This may "undermine democracy," opines Jonathan Chait. There are dozens of articles like this.

After the third debate, the teeth-gnashing over this rose to new levels. The New York Times' A-1 headline was that Trump won't accept the legitimacy of a loss.

The Times, Lind, Chait, and the scores of like-minded journalists are correct to chastize Trump for his rhetoric, but fairness requires us to recall that it's not unprecedented in recent American history.

Hillary Clinton in 2002—almost two years after George W. Bush won the election, and well after newspaper recounts established he would have won any of the recounts ordered by lower courts or the Gore campaign—said Bush was "selected" President rather than elected, according to Newsweek (h/t Jim Geraghty). She was a sitting U.S. Senator at the time.

"Bush v. Gore did steal the election," Chait wrote in 2012, calling it a coup. Liberal James Fallows wrote a piece headlined "5 Signs the United States is Undergoing a Coup," with the agreement of liberal scribe Michael Tomasky. This was all part of a campaign of intimidation, quarterbacked from the liberal activists closest to Hillary Clinton, to threaten the Supreme Court with charges of illegitimacy if they didn't uphold Obamacare's individual mandate.

Bush v. Gore was a fitting comparison for Fallows to make because around that time, Democratic lawmakers and liberal leading lights were explicitly trying to undermine the presidency by calling the election results illegitimate, and President Bush illegitimate.

I attended a Congressional Black Caucus hearing in the weeks after the election when one CBC member called the 2000 election a "coup d'etat." This was a member of Congress talking about the president. Jesse Jackson, less than a year after receiving the Medal of Freedom from Bill Clinton, consistently accused Bush of a coup.

Four years later, Democrats held a charade on the floor objecting to Ohio's electoral votes. Undermining President Bush's legitimacy was politically valuable to them. This was a mantra on the Left long before the 2004 election, when many on the Left were warning the election would be rigged ahead of time

Hillary Clinton, the Democratic nominee, continues to this day to say that the Supreme Court—not the voters or the electoral college—determined the 2000 election. That's undermining democracy by spreading misinformation.

Al Gore and John Kerry, to their credit, both conceded and granted the legitimacy of their losses. Trump may not do the same, which would be incredibly irresponsible. But if President Obama is going to blame Rob Portman for not doing enough to battle Trumpism, he needs to explain why he would be an opening act for Jesse Jackson in 2002, in the wake of Jackson's regular "coup" charges.

Trump shouldn't try to erode the public's trust in our Republic. Neither should Democratic lawmakers and liberal journalists.

Timothy P. Carney, The Washington Examiner's senior political columnist, can be contacted at tcarney@washingtonexaminer.com. His column appears Tuesday and Thursday nights on washingtonexaminer.com.