There were a handful of tries to knock off Republican incumbents on primary election night last month. But when the dust settled, the ink dried and the votes were tallied, only one challenger succeeded: Peter C. Breen. A 37-year-old Lombard resident, Breen has all the calling cards of a conservative. He’s pro-life and against same-sex marriage. He emphasizes cuts and fiscal prudence over new taxes. He helped re-elect former President George W. Bush in 2004 and even appeared on Fox News last year to rail …