It is difficult to understand the reasoning of the federal appeals court panel that permitted Wisconsin officials to enforce a controversial voter ID law less than two months before Election Day. That's partly because the panel's five-paragraph order, issued late Friday only hours after oral arguments, offered the barest rationale for lifting the stay that Judge Lynn Adelman of the federal district court had placed on the law in April.

Adelman issued a remarkably thorough 70-page opinion finding that the law violated both the Voting Rights Act and the Constitution by making voting harder for a substantial number of Wisconsinites — disproportionately those who are minority and poorer, and who tend to vote Democratic. (The law, passed in 2011 by a Republican-controlled Legislature but since tied up in lawsuits, requires prospective voters to present a government-issued photo ID, like a driver's license or passport.)

Regardless of how the appeals panel eventually responds to the merits of Adelman's ruling, its interim decision to lift the stay has thrown the Wisconsin midterm elections into chaos.

Rick Hasen, a professor of election law at the University of California, Irvine, called the panel's decision "a big, big mistake" on his blog. He added: "It is hard enough to administer an election with set rules — much less to change the rules midstream."

Voter ID laws seem like an easy rallying cry. Who doesn't support "electoral integrity"? And how hard is it to get an ID anyway? But as judges across the country have increasingly come to understand, there is essentially zero in-person fraud, which is the only kind that voter ID laws would stop. "Virtually no voter impersonation occurs in Wisconsin," Adelman found in April.

On the other hand, tracking down the underlying documents to get an approved form of ID can be a forbidding process, particularly for those otherwise-eligible voters without a birth certificate, or without easy access to transportation. As Adelman found, Wisconsin's law "will deter or prevent a substantial number of the 300,000-plus voters who lack an ID from voting."

In short, voter ID laws don't stop fraud. They stop otherwise-eligible voters from coming to the polls.

FROM AN EDITORIAL IN THE NEW YORK TIMES