It would take a big polling error for Republicans to fall below 51 seats.

Every two years, when I look at the fall polling in Senate races, I use the same basic framework, which I explained here and here:

First, I note that mid-September polls are typically not the last word in these races, which tend to move in a wave direction nationally, either in the direction of reflecting toward the president’s approval rating (in midterm years) or with the presidential race (in presidential years). Second, I look at the RealClearPolitics poll averages with particular attention to how far each candidate is from the magic 50 percent mark and what share of the remaining undecided vote would need to break in the Republican candidate’s direction to get to 50. I typically also flag how robust the data are for each race — how many polls make up each state’s average, and how many of those are relatively recent.

My approach is, I stress, a metric, not a model. I’m not making mathematical predictions or odds. I’m just collecting the data we have in one place, asking how much room there remains to move based on the current polling, and drawing from that some conclusions about what races are most winnable if one party or the other has the wind in its favor.

We have fresh polling in 13 Senate races. Some of those, such as Maine, just sweep uncompetitive races further from center stage. Montana polling confirms that late efforts to generate buzz for Jon Tester are wholly at odds with the public polling.

What we see from the rest is an increasingly clear stratification of the Senate races. Unless the polls are very wrong, Democrats will pick up no seats, and Republicans will bank easy wins in West Virginia and Montana; there’s one pickup (Ohio) that modestly favors Republicans (not by much in the poll average, but with the state likely going heavily for Donald Trump), three Midwestern pickups (Pennsylvania, Michigan, and Wisconsin) where Republicans trail but could win if there’s a modest poll error, and two Sun Belt races (Arizona and Nevada, with New Mexico as the extreme outlying third) where a larger poll error could mean the GOP takes the seat with a good Election Day showing. All six of those latter races feature Democrats (five incumbents and Elissa Slotkin in Michigan) clustered between 48.4 and 49 percent of the vote. New Mexico is the most implausible of those because the Republican candidate is still polling below 40 percent, while the rest range from Sam Brown at 43.8 percent in Nevada to Eric Hovde at 47 percent in Wisconsin.

Let’s look at the momentum. First, measured against the mid-September polls:

The closing of the gap between the presidential and Senate tickets has put Bernie Moreno slightly in the driver’s seat, kept Sam Brown, Hovde, Mike Rogers, and Dave McCormick in the game, and even brought Kari Lake to the hopeful outskirts of competitiveness. It’s also carried Larry Hogan out to sea despite running an admirable race against a partisan hack.

But how have these races broken late? Compare with the state of the races two weeks ago:

Arizona, where Lake had run double digits behind Trump, has had the strongest late momentum in the direction of the presidential race. But Pennsylvania and Wisconsin have lagged. The reality is that those races will disappoint Republicans unless there’s a really strong Election Day turnout for the party.

How well did the final polls do in 2022 compared to the final poll averages?

Unsurprisingly, the big polling misses that underestimated Republicans were all in red states that were lightly polled because they were not competitive (the relevant parallels this year would be Nebraska, Indiana, and Missouri), while the big polling errors in the other direction were deep-blue states such as Colorado, Washington, and Vermont where only hopeful Republican pollsters were in the field. The more disappointing reality is that several competitive races — Republican wins in Ohio, Wisconsin, and North Carolina, and losses in Nevada, Georgia, Pennsylvania, Arizona, and New Hampshire — underperformed by two to eight points in the 2022 turnout environment. The challenge for the GOP is creating a different environment in the much larger turnout world of a presidential race, as Democrats did between 2010 and 2012.

My final prediction, as things stand now, would be that the GOP takes the Senate with 52 seats, picking up West Virginia, Montana, and Ohio, while holding serve in all the seats it’s defending. That’s progress, but also a lot of lost opportunities. It would take a big polling error to fall below 51 seats. But it actually would not take a very large error in the other direction, well within the usual run of presidential elections, to get Republicans to 55 or 56 seats. So, while confidence may be in short supply, hope abounds. It’s the kind of hope that will lead to a lot of broken hearts if it falls short.

UPDATE: A few late polls arrived last night from Ohio, Arizona, and Texas after I finished this. Take them with a grain of salt, because these are largely from Republican-leaning pollsters such as Trafalgar, but they show a further surge for Moreno in Ohio, Kari Lake tied in the final polling, and a widening lead for Ted Cruz. Here are the big chart and the late-momentum chart, updated with those.