George Will: IN the last 24 elections, since 1912, winners of the presidency won a plurality of the states along the Mississippi. Today the Republican presidential candidate with perhaps the most impressive resume says: Republicans should assume that in 2008 they will lose Ohio (20 electoral votes), where the state party's corruption and incompetence cost it the governorship, a U.S. Senate seat and a House seat in 2006. So the GOP candidate must carry Iowa, Wisconsin and Minnesota (27 electoral votes). In 2004, George W. Bush narrowly carried Iowa and narrowly lost Wisconsin and Minnesota, the only state that has voted Democratic in eight consecutive elections. The man with the impressive resume is Tommy Thompson, who says he can carry those three Midwestern states. He served four terms as Wisconsin's governor, and four years (2001-2005) as secretary of health and human services, where he presided over a $580 billion budget, larger than the combined budgets of the eight larges...