If vote totals for presidential candidates are so close that provisional ballots are needed to determine a winner, the race could take more than two weeks to decide. Polls show that the state's race between President Bush and Sen. John Kerry is too close to call.

Blackwell's order followed the Ohio Republican Party's challenge of the registrations of 35,000 voters last week, after the GOP said mail sent to the voters came back unreturned.

Two Cleveland-area women asked a federal judge Tuesday to stop the Republican challenges, saying the party is trying to disenfranchise thousands of voters because of minor postal errors.

Blackwell's order on provisional ballots directs election boards to hold hearings on any pending challenges to voter registrations and rule immediately on the challenges.

If the board rules against a voter, election officials should flag the person's names as a candidate for possible removal from registration lists, Blackwell said.

If those people try to vote on Election Day, they'll be allowed to cast provisional ballots as long as they go to the precinct where they currently live.