Trump is a legitimate president. But we need to know how he won.

The hallmark of a democracy is the peaceful transfer of power following an election. An essential, if painful, corollary of that rule is to accept the outcome of the election even when its conduct may have been marred, even when questions linger about the nature of the victory.

That was the difficult lesson of the 2000 campaign. But for a flawed butterfly ballot in Palm Beach County that diverted confused voters to Pat Buchanan, Al Gore would likely have been declared the winner in Florida and thus the 43rd president.

But there are no do-overs in elections, especially presidential ones. There may be flaws and disputes. But at some point, after the procedures established by the rule of law have run their course, the country needs to accept the result, however difficult it may be.

So for all of John Lewis’s heroic service to his country, the Georgia congressman’s assertion that Donald Trump is not a “legitimate” president was not appropriate or helpful. Indeed, it is not even the right way to think about the question. Trump is a legitimate president because our system demands finality and acceptance even in the presence of uncertainty. Posting an asterisk next to an election result is not healthy for democracy.