A special U.S. Senate election to replace the late Democratic Sen. Frank Lautenberg can be held in October, as it was scheduled by Republican Gov. Chris Christie, a state court ruled Thursday.

The ruling could be appealed. And while it keeps an election on course it does not seem likely to chill criticism of the popular governor for how he chose to replace Lautenberg, the Senate's oldest member, who died last week at age 89.

Four Democrats and two Republicans have filed petitions to run in the Senate race to complete Lautenberg's term, with three early polls showing Democratic Newark Mayor Cory Booker as the front-runner.

Christie scheduled the election for Oct. 16. A group of Democrats sued, saying it should be held Nov. 5, the day voters are going to the polls in the general elections anyway.

Christie's critics have complained that holding the election in October will cost taxpayers unnecessarily. Officials say each election costs the state about $12 million to run.

Judge Jane Grall wrote Thursday that objections to the costs of the election are policy matters that aren't questions for the court.