Will you have to vote for one or two U.S. senators?

A judge in Chicago could decide if Illinois residents will vote twice to fill President Barack Obama's old Senate seat on Election Day.

The case stems from a lawsuit two voters filed last year because Gov. Pat Quinn didn't call the special election they say is required by the U.S. Constitution.

A federal judge could rule on the issue Monday after getting the case back from an appeals court.

The special election would be to pick an interim replacement to bump Sen. Roland Burris and serve the remaining weeks of Obama's old term until a new senator is inaugurated in January.

Burris was appointed by Rod Blagojevich just weeks after Blagojevich was arrested in 2008 on federal corruption charges. The former governor has pleaded not guilty to charges that accuse him of trying to sell or trade the Senate seat.