WASHINGTON - The Supreme Court jumped into the legal battle over voter identification laws Friday, ruling that Arizona may require voters to provide photo IDs when they cast their ballots next month.

The justices cautioned that they were not issuing a ruling on the constitutionality of Arizona's law. "As we have noted, the facts in these cases are hotly contested," the court said in an unsigned five-page order.

Indeed, the court said it would review the legal challenge to Arizona's Proposition 200, approved by the state's voters in 2004. The law requires voters to prove citizenship when registering to vote and to show photo IDs when they go to the polls. The law was meant to make sure illegal immigrants weren't casting ballots...