Finally, the battle for the Senate will be decided by the battleground-state races, where the presidential ticket will play an outsized role in determining the fate of the down-ballot candidates: Virginia, Nevada, Ohio, and Florida. The presidential race in all four of those states is close, but Obama has gotten late post-convention momentum that’s boosting his prospects in all three. In Ohio and Florida, less-than-stellar Republican nominees Josh Mandel and Rep. Connie Mack desperately need Romney to win their states by a healthy margin to pull them across the finish line. That’s looking less likely by the day.
In Virginia, both former Sen. George Allen and Tim Kaine are as reliant on their presidential nominees as anyone in the country. If Obama wins the state, likely propelled by high minority and youth turnout, Kaine is in good shape. If Romney wins, though, it’s a very good sign for Allen’s prospects, and would be a signal that the enthusiasm gap asserted itself in favor of the GOP.
Sen. Dean Heller is the stronger candidate in Nevada, but if the Democrats’ turnout machine replicates itself in 2012, he could find himself in a closer-than-expected race with Rep. Shelley Berkley. If there’s one state that confounds the weak economic data, it’s Nevada, which looks primed to back Obama despite very high unemployment and a foreclosure crisis. That dynamic could boost Berkley, if she holds her own in the campaign.
So let’s go to the Senate scoreboard. If Republicans still manage to pick up seats in the deeply conservative states: Nebraska (a near lock), North Dakota (far from a lock), and Montana (another close race) but lose Maine, Massachusetts, and Wisconsin while fumbling away Indiana, we’re at the status quo. There are other paths to an even-steven Senate breakdown: If Republicans hang on to Indiana but a strong Democratic turnout in Nevada ousts Heller, same situation.
Republicans, meanwhile, need more of an inside straight. Hang on to the seats in Republican states (which alone account for three pickups), hold Massachusetts, and pick up Wisconsin and Virginia. That would give them four seats, enough for a bare 51-49 majority. An upset in Connecticut would allow for a little more wiggle room.
At the beginning of the year, it was hard to envision Democrats holding a Senate majority, given both the Republican-friendly landscape of states contested and the expectation that there would be many competitive races in battleground states. Not only have Democrats held their own in the solidly Republican states, but Republicans haven’t been able to threaten seemingly-vulnerable incumbents, like Sherrod Brown, Bill Nelson, Debbie Stabenow, and Bob Casey. (Shockingly, Sen. Jon Tester could reasonably be the only Democratic senator to fall.)
There’s enough uncertainty, and enough races still in play, that Republicans could still muster a net of four or five seats. But those prospects are looking dimmer by the day.