Trump is trying to undermine our democracy. It’s un-American.

PRESIDENT TRUMP tweeted Thursday that the presidential election results “may NEVER BE ACCURATELY DETERMINED” because of the “new and unprecedented massive amount of unsolicited ballots.” “RIGGED ELECTION in waiting,” he exclaimed in another tweet.

This is not the first time Mr. Trump has cast doubt on the legitimacy of a vote that polls indicate he is likely to lose, and it will not be the last. Rather than internalizing the notion that the coming election is likely to be fraudulent — which experts adamantly insist is not the case —...