|Sens. Joe Manchin (D-WV) and Heidi Heitkamp (D-ND)|
However, a problem is starting to emerge for the Democrats that hasn't been really reported for 2016 and beyond, and though anyone considers anything other than 2014 Midterms or 2016 White House talk loathsome at this point, it's worth noting: three red state Democratic senators are seen as seriously exploring a run for governor in 2016. This may seem presumptuous to discuss right now-this is eons away politically, but all three add a complexity to future Senate math that is worth noting, particularly considering the long game of the Senate.
The reason for this is simple. If the Democrats manage to keep the Republican victories below five this cycle (not the most likely scenario, which is six, but certainly a possibility if the Democrats hold all Obama-states plus half of Hagan/Pryor/Begich/Landrieu), they will enter 2016 with enormous potential. Thanks to the 2010 GOP wave, the Republicans will be forced to defend Senate seats in blue/blue-purple territory like Pennsylvania, Wisconsin, New Hampshire, Illinois, and Ohio. This will give the Democrats a decent shot at winning a number of seats to help them in future cycles. The reality of the Senate is that with the states roughly even in terms of numbers (President Obama won 26 states vs. Gov. Romney's 24 states), until there is a demographic shift in the Midwest to the GOP or in select states like Georgia/Arizona/Texas for the Democrats, neither party has a particular advantage in the Senate. Picking up as much friendly territory while retaining your sporadic "unfriendly" seats is key to maintaining a majority, something Harry Reid has been smart about over his eight years in the majority.
However, three Democratic senators who won election in 2012 have openly and frequently talked about the prospect of running for governor in 2016: Joe Manchin (WV), Heidi Heitkamp (ND), and Claire McCaskill (MO). It's worth noting that all three of these senators have actually run for governor in the past, though Manchin is the only one to do so successfully. Each is assuredly the most important Democrat in their home state and would get a cleared field for the governor's mansion, something all are savvy enough to be aware of, and I would wager that with Manchin in particular they would start as the prohibitive frontrunner (Heitkamp and McCaskill would probably go in with even odds, though better than any other Democrat in the state and could most definitely win the chief executive spot).
There are a couple of problems here for the Democrats. These states are deeply Republican on a federal level even if they aren't there on a gubernatorial level (both Missouri and West Virginia have Democratic governors). If any of these three senators were to step away from their seats, there is little indication that the Democrats could hold them, and a couple of monkey wrenches are thrown in with this predicament. I'm not enough of an expert on North Dakota law to know whether or not Heitkamp would get to pick her own successor, but I would assume she would push extremely hard for her seat to stay in Democratic hands.
Let's assume, for the sake of argument, that all three are able to pick their own successors. That still poses a robust challenge for 2018. As we have seen this year in South Dakota, West Virginia, and particularly Montana, Democratic incumbents matter. All three of those states, despite in the latter two cases a pretty robust bench, are lost causes for the Democrats this cycle, but they didn't have to be if their three incumbents had run again. Look at the other four red-state Democrats running this cycle: none of them have pulled away in a major way from their GOP opponent, but none of them have gotten to a point where they are doomed; I can say with confidence if Rockefeller, Baucus, and Johnson had all signed up for another term, we wouldn't be talking about a GOP majority in January, just about how many seats the Republicans would pick up. One of the biggest and most important lessons learned by Democrats in 2010 is how to make sure to use an incumbent's personal brand to defy national trends (someone like Blanche Lincoln learned this the hard way when she tried to have her cake and eat it too without putting her personal brand first-if she had run the campaign of a Mary Landrieu, her race would have been MUCH closer). Eventually, of course, these incumbents will have to retire, but 2018, particularly if Hillary wins the White House, would be an awful time to do it and none of these senators are particularly old in terms of the U.S. Senate. Though none of these senators comes across as "White House adjacent," it would behoove Harry Reid to consider the axiom that "all senators look in the mirror and see a president" and do some ego-catering in the next couple of years to keep them on his roster.
So this is something worth considering with the math of the Senate over the next couple of years: the decisions of these three senators could have a profound affect on where the upper house goes in terms of partisan makeup.