Indiana Demo chair raises threat of challenging GOP crossoversAssociated Press - April 3, 2008 5:04 PM ET INDIANAPOLIS (AP) - Indiana's state Democratic chairman says the party will challenge any long-time Republicans who try to use the state's open primary to create "mischief." Chairman Dan Parker says he's concerned that some Republicans might use the crossover interest in the presidential race between Barack Obama and Hillary Rodham Clinton as an opportunity to target other Democrats lower on the May 6th ballot. Talk show host Rush Limbaugh has urged conservatives in open primary states to vote for Clinton. The advice is...