Sabato sizes up the Senate races:
We now favor Republicans in four Democratic-held seats: Montana, South Dakota and West Virginia, as well as — in a ratings change — Arkansas, where Sen. Mark Pryor (D) appears to be at least a slight underdog to Rep. Tom Cotton (R) in a reddening state. Assuming Republicans can win those, they have roughly even odds to win in three other states where there are Democratic incumbents: Alaska, which we’ve long classified as a Toss-up, and Louisiana and North Carolina, which we’re switching back to Toss-ups after having them in that category for much of last year. It’s possible that the race for the Senate will come down to these three Toss-ups, with the party that wins at least two of the three controlling the Senate.
Sean Trende expects Obama’s approval numbers to have a major impact on the result:
If the president’s job approval is still around 43 percent in November — lower than it was on Election Day in 2010 — the question would probably not be whether the Democrats will hold the Senate, but whether Republicans can win 54 or 55 seats. Given the numbers right now, that should not be unthinkable.
But there’s a flip side to this. If Obama’s job approval does bounce back — which is exactly what happened in 2012 — there’s a reasonable chance that Republicans could walk away from this cycle with just a handful of pickups.
In a later post, Trende explains why the number of seats the GOP wins matters so much:
[I]f the GOP wins a bare majority in 2014, the odds are very, very good that the Senate will revert back to Democratic hands in 2016. In fact, if GOP gains are confined to the “traditional seven” Democratic races (the three open seats and the four incumbents in states Mitt Romney carried), they’re still favored to lose the chamber two years later. On the other hand, if Republicans get to 54 seats, their chances of retaining control are very good, and given the horrific playing field for Democrats in 2018, they would be extremely unlikely to lose it that year.