I have written this piece for Slate. it begins:

In separate rulings on Thursday, two federal courts had the same message for minority voters making credible claims of potential disenfranchisement: Your arguments may be good on the merits, but it’s too late. These courts, which were examining onerous voting rules in North Dakota and Kansas, took their cues from the U.S. Supreme Court, which has embraced an unfortunate rule that even serious voting problems cannot be remedied in the period before Election Day….

Both of these cases relied heavily upon what I’ve termed the “Purcell Principle,” which guides courts against making last-minute changes in voting rules out of fear of voter and election-administrator confusion.

The concern about voter and election-administrator confusion is a real one, and certainly courts should consider such factors in deciding whether to grant emergency relief before an election. But the Purcell Principle deviates significantly from how courts usually consider whether to grant emergency relief, which generally involves looking at how likely it is that plaintiffs will ultimately win their argument, the burdens on each side depending upon how the court rules, and the public interest.

In the North Dakota case, for example, the court appeared convinced that voters were being disenfranchised, and the appeals court had explicitly invited these voters to come back if their voting rights were being burdened. In such a case, the risk of confusion is outweighed by the damage of failing to enact a simple rule that would prevent actual disenfranchisement of voters. It is the same with the Dodge City case. The confusion here would appear minimal, and though the state raised the risk of double voting, there was no good evidence that was a problem that could not be solved by having voters cast provisional ballots at the second polling place.

Ultimately, the message that the Purcell Principle sends is this: Sometimes voters are going to face actual disenfranchisement, but when the evidence of a problem comes too close to the election, the courthouse door will be closed