Senate candidates Joe Donnelly (D) and Richard Mourdock (R). (WIBC.com file photo)

Tuesday's second and final Senate debate will remain open to the public, despite a union push to corner the market on tickets.

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The Indiana Debate Commission considered closing the New Albany debate among Republican Richard Mourdock, Democrat Joe Donnelly and Libertarian Andrew Horning, after a United Auto Workers bus convoy gobbled up 300 of the 500 available seats. Terre Haute Tribune-Star editor Max Jones, the commission president, says the commission talked with the union, the three campaigns, and debate host IU Southeast, and decided to leave the planned live format unchanged.

The university will increase security, and can remove anyone who's disruptive. Jones notes the debate moderator -- in this case, former Indianapolis Star editor-in-chief Dennis Ryerson -- always instructs the audience beforehand not to cheer, boo, or otherwise react during the hourlong debate. Jones says the union has promised to observe the rules, and says he expects the forum will be uneventful.

The first Senate debate was held without a live audience. The two gubernatorial debates have been in front of an audience, but next week's third and final faceoff will not be.

The UAW has endorsed Democrats' entire statewide ticket, but feelings are particularly high in the Senate race, where Donnelly and Mourdock have repeatedly clashed over Mourdock's lawsuit attempting to derail the fast-track bankruptcy deal for Chrysler. Donnelly contends the deal saved thousands of Hoosier jobs. Mourdock argues the deal violated bankruptcy law and cheated Indiana pension funds of their rightful place in the repayment line.