With Democrats defending nearly twice as many Senate seats as Republicans in 2012, the GOP has an excellent chance of taking the upper chamber and holding majorities in both houses of Congress. According to RealClearPolitics, or RCP, there are eight toss-up races that will dictate control of the Senate. Of those, independent Angus King is likely to win Maine, Democrat Bill Nelson is likely to win re-election in Florida, and Republican Dean Heller is likely to win Nevada's Senate race. That leaves the races in Massachusetts, Missouri, Virginia, Montana, and Wisconsin as the five races that will most likely tip the balance of power. My analysis and predictions are below.       

Massachusetts: Scott Brown (R) versus Elizabeth Warren (D) -- Probably the most interesting race in the country, polls have the two nearly deadlocked, although former Harvard Law School Professor Elizabeth Warren's campaign has been beset by the controversy over her 1/32nd Native American heritage and questions about whether she exploited it for career gain. As stupid as identity politics are, it seems as though Harvard pushed Warren's minority status more than she did, making the controversy a little perplexing and, perhaps, overblown. 

Unfortunately for the Brown campaign, this story is unfolding in May and not September, and Warren will have plenty of time to recover. I take particular interest in this race, as I'll never forget those ominous words on a late summer 2002 morning in Cambridge, Massachusetts. What is assumpsit?  It was my first class at Harvard Law School, and it was the first of many pointed questions from Elizabeth Warren, my 1L contract's professor.  Warren was as universally admired as any professor at Harvard -- by both conservatives and liberals. While I shared that affection, I certainly wouldn't want her as a U.S. Senator, and no Republican should.  She is brilliant, likeable, and tough.  If elected, she will immediately become one of the intellectual leaders of the Senate.  (Prediction: With apologies to Scott Brown, Elizabeth Warren wins a close race and becomes a staple for years to come).

Missouri: Claire McCaskill (D) versus Sarah Steelman (R) -- Former Missouri state treasurer, Sarah Steelman, who still must win the Republican primary in August, is running ahead of Democratic incumbent Claire McCaskill in several polls. McCaskill, who has tried to maintain a reputation as a moderate, is finding that posture harder to defend with her consistent support of President Barack Obama's policies. Steelman, on the other hand, has the pedigree that is ideal for the current environment. She has a background in economics and has been active in pushing state pension systems to divest from investments connected to terrorism. Her understanding of the nationwide pension crisis and its roots in excessively generous labor benefits makes her an especially attractive candidate. 

When I asked her what best prepared her to serve in the Senate besides her role as the former state treasurer, she cited running a small business and being a mom. She's also a big fan of Michael Lewis's last books, Boomerang and The Big Short, which should be required reading for any member of Congress.  (Prediction: Steelman ousts McCaskill in one of the biggest pick-ups of the year for Republicans).

Virginia: George Allen (R) versus Tim Kaine (D) -- For former Senator George Allen, this is a second chance at a political career. Once heralded as a potential presidential candidate, Allen saw his career derailed by his infamous Macaca comment, questions about his racial views, and ultimately his surprising Senate race loss in 2006 to current incumbent James Webb.  Now, Allen is squaring off against former Virginia governor and former DNC Chairman Tim Kaine.  Most polls have the two in a virtual deadlock, but Virginia, which Obama picked up in 2008, is leaning red once again.  (Prediction: Allen vindicates himself and reclaims his perch in the Senate in one of the closest races in the nation).

Wisconsin: Tammy Baldwin (D) versus Tommy Thompson (R) or Mark Neumann (R) -- The primary battle between former Republican Governor and former Secretary of Health and Human Services Tommy Thompson and former congressman Mark Neumann foreshadows the other political battle taking place this electoral season. That is the one between Tea Partiers and the Republican establishment. Thompson is seen as the more electable, establishment candidate for a seat that was held for 24 years by retiring Democrat Herb Kohl. The winner will face Democrat Tammy Baldwin, whom Thompson is leading in most polls. Thompson also leads Neumann in the polls and will benefit by more significant name recognition in the state. 

Neumann supporters will point to the party leadership's ill-considered decisions to support candidates like Arlen Specter over Pat Toomey and Charlie Crist over Marco Rubio. Thompson supporters can point to the disastrous campaigns of Sharron Angle and Christine O'Donnell as an argument for electability. Whoever is the candidate, Wisconsin is an important state to watch given that it has been at the forefront of the labor controversy and out-of-control public expenditures over the last few years.  It also has a hugely important gubernatorial election this year as well. (Prediction: Thompson wins the primary and defeats Baldwin, giving Republicans another big pick-up seat). 

Montana: Jon Tester (D) versus Denny Rehberg (R) -- Incumbent Senator Jon Tester -- who sports the most formidable flat-top hairdo in Congress -- will battle cowboy-hat-wearing Congressman Danny Rehberg. If anybody looks the part of a senator from Montana, it is Rehberg, who manages a ranch and whose congressional career has not been without controversy, having made questionable comments about gays and people with AIDS. Nonetheless, Tester's support of Obamacare is likely to make him the latest Blue Dog Dem from a conservative state to lose re-election. (Prediction: Rehberg ousts Tester and Republicans pick up another formerly Democratic State). 

With my calculation, Republicans are likely to pick up the 51 seats they need to take control of the Senate. If Republicans can accomplish that, independent Angus King may also caucus with Republicans in order to join the majority ranks.  All of this means that even if Obama is lucky enough to win a second term, his lame-duck presidency will begin on day one. 

Brett Joshpe is an attorney and author in New York City.