COLUMBUS, Ohio -- Ohio is the biggest swing state standing in the way of the Libertarian Party's efforts to place candidates on the November ballot.

The party has filed lawsuits in Ohio and Tennessee against what it says are unconstitutionally restrictive ballot-access laws.

The party's first goal is to get former GOP congressman Bob Barr on the ballot in 48 of 50 states. Some Republicans are worried Barr will play spoiler in a tight presidential contest. He's on the ballot as a Libertarian or independent in 31 states so far.

In the Ohio lawsuit, the party hopes to overturn a state rule that requires a minor party to turn in more than 20,000 signatures 100 days before the primary. If unsuccessful in the lawsuit, party members hope to gather 5,000 signatures to get Barr on the ballot as an independent.