The man in charge of retaining Democrats' Senate majority Wednesday detailed the six states he believes will determine whether he's successful in 2014.

DSCC Chairman Michael Bennet (D-Colo.) (AP)

The states include four Democratic held seats — Alaska, Arkansas, Louisiana and North Carolina — and two GOP-held seats — Kentucky and Georgia. And Democratic Senatorial Campaign Committee Chairman Michael Bennet (D-Colo.) made the case that Republicans will have to come close to running the table.

"This is what the majority in the Senate’s going to come down to," he said. "Republicans have to essentially sweep these races in order to win the majority, winning at least five of the six."

The way the Senate landscape is looking right now, Bennet is probably right.

But implicit in Bennet's statement is the acknowledgement that Democrats face increasingly long odds of holding open seats -- or at least still need to recruit a candidate -- in three red states with retiring Democratic incumbents: Montana, South Dakota and West Virginia.

(Bennet said the DSCC is still recruiting in these states and noted that now-North Dakota Sen. Heidi Heitkmap, for example, wasn't on anybody's radar at this point two years ago.)

If Republicans won those three states, they would have three of the six takeovers that they need to win back the Senate majority. From there, if no other states come into play, they would indeed need to win five of the six races he described.

Democrats have a fighting chance in all six, to be sure, and should be favored to hold their Senate majority. But keep in mind that all six are taking place in states that Mitt Romney carried in 2012 despite losing the presidential race, and five of the six are firmly in the "red" category.

In other words, all Republicans need to do to regain the majority is to win in red states.

It won't be easy, of course — especially given that they face incumbents in all four Democratic states in the DSCC's six-seat firewall. The DSCC is fond of citing the fact that Republicans have beaten just three Democratic incumbents over the last decade.

That may be true, but it's a little misleading.

The reason Republicans have beaten so few incumbents over the last 10 years is in part because so many red-state Democrats have retired. And when they have run good candidates against red-state Democrats seeking reelection, they've been successful.

Going back to 2004, nine of 25 Democratic senators facing reelection in red states opted to retire. Republicans won seven of those nine states.

When those incumbents sought reelection, they often escaped strong challenges. In fact, only five of the 16 Democrats who ran again were top targets: Tom Daschle (S.D.) in 2004, Mary Landrieu (La.) in 2008, Blanche Lincoln (Ark.) in 2010, and Jon Tester (Mont.) and Claire McCaskill (Mo.) in 2012.

Two of the five lost (Daschle and Lincoln), while McCaskill benefited from a deeply flawed GOP nominee in Todd Akin.

The fact is that when Republicans have solid candidates in red states, the results have been very winnable races.

As for 2014, it remains to be seen who will emerge from GOP primaries in states like Alaska, Georgia and North Carolina. And in each state, there is at least some cause for concern if you are a national GOP leader — be it Joe Miller in Alaska or Paul Broun in Georgia.

But if Republicans can land the right kind of candidates in these states -- a very big "if" given the party's recent track record, we know — they may very well test the Democratic firewall that Bennet constructed Wednesday.

Updated at 4:40 p.m.