COLUMBUS, Ohio – A weeklong period in which Ohioans could register to vote and immediately cast a ballot ended Monday with turnout that didn't quite match the expectations of election officials – or the campaign predictions that preceded it.

Early returns showed about 3,000 voters in Ohio's four largest counties took advantage of the disputed policy, a surprisingly low turnout to some elections officials.

The window was expected to benefit Democrat presidential candidate Barack Obama, as his campaign and advocacy groups pushed Democratic-leaning groups such as college students and low-income voters to the polls.

Through Sunday, 1,152 voters had taken advantage of the policy in Franklin County, which includes Columbus. In Montgomery County, home to Dayton, roughly 250 people had used it. And in Hamilton County, where Cincinnati is located, about 454 voters had taken advantage of the window by midday Monday.

Another 1,000 or so were expected from Cuyahoga County, which includes Cleveland and is the state's most populous county.

“With all the hoopla we were anticipating a whole lot more,” said Montgomery County Board of Elections Director Steve Harsman.

The Ohio GOP sued in federal court to stop the voting window but was unsuccessful.

Republicans argued that Ohio law required voters to have been registered for at least 30 days before they could be given an absentee ballot. They said the window could lead to widespread voting fraud because officials wouldn't have an opportunity to verify registration information before ballots were cast.

Ohio, with 20 electoral votes, remains a toss-up state. In 2004, Ohio put President Bush over the top and gave him a second term.