A great day for the integrity of American elections. Now we just need such laws in 49 other states and the District of Columbia.

The Supreme Court ruled yesterday that Arizona may enforce a new state law requiring voters to show a photo identification card at the polls on Election Day this year, despite a pending lawsuit by opponents who say the measure will disenfranchise the poor, minorities and the elderly.

In its unanimous five-page ruling, the court did not decide whether the Arizona law was constitutional. Rather, it overturned a federal appeals court in San Francisco that would have blocked enforcement of the law until the opponents' suit could be decided.

That would take too long, the court said, noting that, "in view of the impending election," Arizona needed "clear guidance."

The actual impact of the Arizona law, which was approved in a statewide referendum two years ago but has not yet been applied, was still too unclear to justify changing the state's plans so close to Nov. 7, the justices said.

What is the requirement?

Arizona, which borders Mexico and has seen a surge in migration in recent years, is one of several states that have recently enacted a photo-ID requirement in response to reports that illegal immigrants and other ineligible voters have been casting ballots.

The Arizona law requires voters not only to present proof of citizenship when they register but also to present a photo ID when they go to the polls. Those without a photo ID may cast a provisional ballot, but their votes do not count unless they can produce a valid identification card within five days.

It requires proof of identity and residence -- hardly unreasonable. And it provides a method for those who don't have the identification on Election day to have their vote count. The IDs are even free if you cannot afford them.

Now if only we could find a way to require proof of citizenship as well.

By the way, while the Court's opinion said it is not ruling on the merits of the case, this decision makes me believe that they lean in favor of the identification requirement. If there was a serious probablility of the anti-identification forces winning, they would have enjoined enforcement.