A Lake county, Indiana, superior court judge yesterday ordered early voting sites in heavily Democratic cities Hammond, Gary and East Chicago to remain open in a decision that could affect the presidential election in the battleground state.

In her decision, Judge Diane Kavadias Schneider dismissed complaints from local Republican officials trying to block the sites on the grounds they violated local election rules and created a risk for voter fraud.

Since local Republicans first sought to close the sites two weeks ago, the case has drawn attention from the presidential campaigns of both John McCain and Barack Obama because Indiana is a swing state.

"This is one of a dozen-plus legal actions that our campaign is paying attention to," said Ben Porritt, a spokesman for the McCain-Palin campaign. "Most importantly, the goal of our campaign is to ensure that all eligible voters have an opportunity to vote, and their votes be counted. We obviously back early polling locations, as long as they are done according to state law. While we disagree with this decision, we will continue to monitor any further legal action that takes place."

Yesterday's ruling was hailed by Democrats because it means more voters in a heavily Democratic region of Indiana have easier access to the polls. In the past, voters had to go to Crown Point, roughly 24 miles (38.6 kilometres) away from East Chicago, to cast early ballots.

"Early voting has been a great success so far in Lake county. Thanks to Judge Kavadias Schneider's ruling today, thousands of Indiana voters had their rights protected and the opportunity granted to take part in early voting," said Jonathan Swain, the Indiana spokesman for Obama's campaign.

"No matter which candidate or which party they are voting for, all Hoosiers who are eligible to vote deserve the right to have their voices heard in this critical election."

Schneider was appointed by the Indiana supreme court to preside over the case brought by John B Curley, chairman of the Lake County Indiana Republican Central Committee, and Jim B Brown, a member of the Lake county board of elections, and others.

The plaintiffs alleged that early voting sites in the three cities should not have been opened because there was no unanimous vote by the Lake county board of elections approving the locations.

Attorneys from the other side said no unanimous vote was needed by the election board because the three locations - one in each city - are in government offices and not "satellite" voting sites. The election board must give unanimous approval for a satellite voting site. Closing the sites would disenfranchise poor and minority voters, the same attorneys said.

"The decision is a complete victory for voters," said Jonathan Weissglass, an attorney who represented some of the groups fighting to keep the sites open. "People in Gary, Hammond and East Chicago: it's very difficult for them to get to Crown Point. There's not good public transportation. People don't have cars or time to make a trip to Crown Point."

R Lawrence Steele, an attorney representing the plaintiffs, was not available for comment on yesterday.