Democrats currently control 55 Senate seats, meaning Republicans have to net six to take control of the chamber in 2015. Without further ado, here is our list of the top Senate races of 2014, ranked in order of most to least likely to flip:
1) South Dakota (Open D, Sen. Tim Johnson retiring) (Previous rank: 1)
With two former Republicans running as independents and likely to split votes on the Right, South Dakota could have been a better opportunity for Democrats. But Rick Weiland isn't the first-tier candidate the party was hoping for, and it doesn't look like he'll be able to make the race to replace Johnson competitive. Former Gov. Mike Rounds has the surest path of any Republican challenger in the country.
2) West Virginia (Open D, Sen. Jay Rockefeller retiring) (Previous: 2)
Secretary of State Natalie Tennant was always playing from behind against the top GOP recruit, Rep. Shelley Moore Capito, and the president's new EPA regulations aren't doing her any favors in a coal state. Tennant has so far kept on par with Capito's fundraising, but she has a lot of ground to make up running against a popular incumbent in a state that really doesn't like President Obama.
3) Montana (D, Sen. John Walsh) (Previous: 3)
Steve Daines isn't Denny Rehberg, John Walsh isn't Jon Tester, and 2014 is looking a whole lot tougher for Democrats than 2012. That, in a nutshell, explains why Democrats aren't too optimistic about Montana despite the party's strong track record of success there. Walsh's appointment to the Senate in January gives him the benefit of incumbency — sort of — but an internal report from the U.S. Army that the then-adjutant general misused resources has put him on the defensive over his military background, which should be a major strength of his campaign. Just five months into his term, Walsh is clearly the midterm elections' most endangered incumbent.
4) Louisiana (D, Sen. Mary Landrieu) (Previous: 6)
Democrats' struggles at the end of last year, fueled by Obamacare's woes and exacerbated by big-spending conservative outside groups, hit Landrieu hard, but she has built herself back up in the past few months with emphasis on how important her energy committee chairmanship is for Louisiana and a clever ad campaign featuring her famous father. Like all of the red states Democrats are trying to protect, Landrieu wants to make the race as much about local issues as possible, forcing Louisiana energy interests to choose between a Democratic friend or their favored party. If Landrieu can't win outright with a majority in November and the race goes to a December runoff with control of the Senate on the line, staying local could get difficult.
5) North Carolina (D, Sen. Kay Hagan) (Previous: 5)
After being an early target of historic spending from Americans for Prosperity, Sen. Kay Hagan finally has some groups (EMILY's List, Planned Parenthood) coming to her defense. Voters in North Carolina don't like national Democrats, especially President Obama, right now — but they are also sour on state Republicans. Hagan's opponent, state House Speaker Thom Tillis, has been pulled away from the race to finish out a contentious legislative session, which prompted protests outside the capitol and even in his personal office. Tillis is also tied to unpopular cuts to education funding and a controversial state budget. Still, Hagan hasn't seen a noticeable bump in available polling since the advertising evened out.