MILWAUKEE (AP) – Wisconsin Congressman Tom Petri will make a formal announcement about his plans to retire after representing the 6th District for more than three decades. The 73-year-old Republican will talk more about the reasons he decided against running again at a town hall meeting in Neenah late Monday afternoon.  Petri is a centrist Republican at a time when his party has been moving to the right, and he would have faced a rare primary challenge from more conservative candidates. He faced only two Republican primaries since 1996, and he had at least 82 percent support in each. Petri spokesman Lee Brooks recently said the congressman would run for at least one more term. Brooks said last Friday the congressman’s reversal was a result of “several factors” and that Petri would elaborate Monday.