If you were to choose a single race that sums up what's at stake this fall, it would have to be the one in South Dakota. To political insiders in Washington, the matchup between Democratic Sen. Tim Johnson and his Repub-lican challenger, Rep. John Thune, is considered this season's defining contest between the two national parties. While Johnson is a protege of Democratic Majority Leader Tom Daschle, Thune is the hand-picked candidate of President George W. Bush. So it's no surprise that Daschle and Bush have gone all out for their respective men, raising gobs of out-of-state money, recruiting talented...