If there’s one thing that former president Donald Trump has taught us, it’s how toxic to the system it is to question the legitimacy of election results. Mr. Trump continues to lie about his resounding loss in 2020 and insist that other Republicans accept the lie, too. In the Virginia gubernatorial race, Glenn Youngkin, the Republican nominee, has indulged Mr. Trump’s falsehoods while seeking not to embrace them so wholeheartedly as to alienate suburban voters who don’t buy them. Mr. Youngkin, a fresh face in politics, had the opportunity to tell voters frankly that the system worked in 2020. He chose not to.

That made it all the more disappointing to hear Mr. Youngkin’s Democratic opponent, Terry McAuliffe, fanning the flames of suspicion over the weekend among his supporters. Campaigning with Stacey Abrams, who lost a race for governor of Georgia in 2018, Mr. McAuliffe said Ms. Abrams “would be the governor of Georgia today” had not the state “disenfranchised 1.4 million Georgia voters before the election.”

“That’s what happened to Stacey Abrams,” Mr. McAuliffe said. "They took the votes away.”

Unlike Mr. Trump’s wild lies about millions of fraudulent votes, there’s some basis for Mr. McAuliffe’s statement. He was referring to the number of people purged from the voting rolls, for various reasons, between 2012 and 2018; in the year before the election, nearly 700,000 were purged, more Democrats than Republicans; and the person in charge of the operation was Brian Kemp, who was both secretary of state and Ms. Abrams’s opponent in the race for governor.

But as The Post’s Fact Checker has written, many were purged from the rolls for entirely legitimate reasons (such as, they were dead). The turnout in 2018 was higher than in any previous midterm. There is no way to know whether Ms. Abrams would have won if Georgia’s registration laws and practices had been different.

Election expert Richard L. Hasen told the Fact Checker in 2019 that he knew of no evidence to prove that Ms. Abrams would have been elected had the rolls not been purged, but added: "That seems to me to be beside the point: The question is whether Georgia had a good reason to put these suppressive measures in place, and for the most part, the state did not have good reasons.” Which points to the right response, and that is the route Ms. Abrams for the most part has been following: Push for laws and practices that encourage voting, rather than suppressing it.

Mr. McAuliffe would do well to stick to that effort, avoiding unprovable allegations that will contribute to the corrosion of trust.