U.S. Rep. Michele Bachmann and her challenger, Jim Graves, tangled Tuesday on bridges, budgets and retiree programs in their first debate.Graves, a DFLer and St. Cloud hotel executive, was on offense for much of the debate, which was staged at River’s Edge Convention Center and moderated by St. Cloud Area Chamber of Commerce President Teresa Bohnen.It was the first of three debates before the Nov. 6 election pitting Graves against the third-term Bachmann, who’s less than a year removed from a run for the Republican presidential nomination. St Cloud Times