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How Tommy Thompson’s win in Wisconsin changes the Senate majority fight

Former Wisconsin governor Tommy Thompson's narrow victory in Wisconsin's Republican Senate primary on Tuesday not only bolsters his party's chances of winning the seat in the fall election but also betters the GOP's chances of re-claiming the majority in the chamber this November.

Thompson, a former four-term governor of the Badger State, was lambasted during the primary as insufficiently conservative on a whole range of issues including health care.  Of course, that same moderate image works to Thompson's advantage in a general election fight against Rep. Tammy Baldwin where his task will be to win over independents and even some leaning Democratic voters.

In the immediate aftermath of Thompson's win, Democrats were quick to point out that he barely eked out a victory -- not exactly a ringing endorsement of his candidacy by members of his own party. They also note that Thompson not only has been in elected office for forever and a day but that he also served as a cabinet secretary for George W. Bush, who is something short of popular in Wisconsin.

All true. But Thompson is so well defined in the eyes of the Wisconsin electorate that it will be hard to demonize him as a shill for national Republicans. And his demonstrated success of winning statewide general elections is unmatched by Baldwin or any of the other Republicans who were seeking the nomination.

In short: It's hard to argue that Republicans' chances of picking up the Wisconsin Senate seat aren't better today than they were yesterday. (To be clear, the race remains a toss up but one that probably tilts toward Thompson today.) And that has a very real impact on the tight fight for Senate control.

To win back the Senate, Republicans need three seats if Mitt Romney wins the presidency and four if President Obama is re-elected.

One seat -- the open seat contest in Nebraska -- is an all-but-assured pickup for Republicans with state Sen. Deb Fischer (R) holding a wide lead over former senator Bob Kerrey (D).

A second open seat in North Dakota is less of a sure thing -- polling suggests a close race between Rep. Rick Berg (R) and former state Attorney General Heidi Heitkamp -- but to win Heitkamp will need to strongly overperform President Obama in the state. Possible? Yes. Probable? No.

That's a two-seat pickup for Republicans. But, then there is Maine where Sen. Olympia Snowe (R) is retiring and former governor Angus King is a near-certain winner. King, an independent, has not said which side he will caucus with if/when he wins but it's widely assumed he will be a Democratic vote.

Assuming all of the above, Republicans still need to win two seats with the White House or three seats without it to retake the majority. And that's where Wisconsin comes in.

There are five Democratic held seats that both sides acknowledge are toss up races at the moment and are almost certain to stay that way: Missouri, Montana, New Mexico, Virginia and Wisconsin.

Republicans have a narrow edge in Missouri while Democrats are slightly favored in New Mexico.  Virginia and Montana are pure toss ups. Without Thompson, Wisconsin would likely have been tilting Democratic. With him, it looks more like a tilt Republican seat.

Win Missouri, Wisconsin, North Dakota and Nebraska -- and the White House --  while losing Maine and Republicans are the majority party in the Senate.   Win those four states and either Virginia or Montana and lose the White House (and Maine) and Republicans still retake the majority.

Of course, Democrats will have something to say about that -- not only in Maine but also in Massachusetts where Elizabeth Warren (D) is challenging Republican Sen. Scott Brown. With Thompson's victory in Wisconsin, winning in Massachusetts just got that much more important for Democrats to give them a bit of a cushion to retain the majority. Democrats are also making a push against Nevada Sen. Dean Heller (R) but it remains to be seen whether Rep. Shelley Berkley can pull the upset.

To be clear: Tommy Thompson winning isn't the sort of sea change in the battle for Senate control that, say, Snowe's retirement amounted to. But, Thompson as the party's nominee in Wisconsin does strengthen Republicans' hand in a critical open seat race that they absolutely must have if they want to win the majority on November 6.