Where are we on the Senate right now?

Perhaps the biggest news over the last week is that Republican chances of holding at least 51 seats have gradually improved. Five of the six leading forecast methods now have the chances for a Republican majority at about two-thirds, while the sixth (from the political scientists at the Washington Post’s Monkey Cage) continue to estimate a whopping 93 percent chance of a Republican takeover. The Post’s Greg Sargent has a good state-level view of the lay of the land for those who prefer that to the overall model estimates.

I’d still caution everyone about the significant uncertainty involved; only the Washington Post method reaches levels at which it would be a real shock if Democrats kept their majority. There’s also the possibility that the polls are a little off, although as Sean Trende and others (myself included) have said, there’s no particular reason to believe that the results will be better for Democrats than the polls indicate. They could just as easily be better for Republicans.

Why have Republicans moved into a higher position? In a few states, their leads have increased. That’s particularly true in Alaska, where early (and sparse) polling gave incumbent Democrat Mark Begich some hope, but surveys over the last five weeks have shown Republican challenger Dan Sullivan in excellent shape. Mostly, however, what’s happened is a little different.

Earlier in the cycle, Republicans had many pickup opportunities yet only appeared to be safely ahead in West Virginia, Montana and South Dakota. In the last few months, though, Republicans have maintained small leads in some of their target races — and small leads in five states in mid-October are more likely to produce five wins than similar leads in July or August. Meanwhile, Democrats have failed to generate any likely takeovers of their own, with the party’s chances in Kentucky, Kansas, South Dakota and Georgia failing at least so far to turn any of those seats around.

What all this means is that Republican prospects have improved, but the chances for a big Republican blowout have not. Granted, pickups in Iowa and Colorado would be a nice way to put Republicans over the top. But at least so far, they haven’t managed to add potential targets such as Minnesota, Michigan or Virginia to the list of closely contested states, and they remain unlikely to win New Hampshire or North Carolina. The result is that prediction models are converging at 52 Republican seats, not 54 or more.

I’m not playing that down. No matter what the opportunities, I doubt there has been a single point during this election cycle when Republican strategists would not have been satisfied with winning seven seats to reach 52. And just as Democratic hopes to hold a majority are still realistic, so are Republican dreams of an even larger landslide. Still, what’s happening is consistent with Republicans taking advantage of expected opportunities.

Fifty-five Republican senators are a lot more likely to block judicial and executive branch nominations than 51 or 52 would be. They would also be more likely to stick together on reconciliation to kill a Democratic filibuster or to carry out majority-imposed changes of Senate rules.

For all the talk of partisan polarization and parliament-style Congresses in which parties stick together, no party can count on unanimity across the board. Slim majorities are still more difficult to manage. Every seat won this year for Republicans is important insurance against reverses in 2016, when the races will be more friendly to Democratic pickups than this year’s have been for Republicans.

In other words: there’s a lot more to the Senate contests than which party gets the majority.

[Cross-posted at Bloomberg View]

Jonathan Bernstein

Jonathan Bernstein is a political scientist who writes about American politics, especially the presidency, Congress, parties, and elections.