Split Ticket

Earlier this year, we introduced our quantitative Senate model. At that time, Republicans were projected to take an outright majority in the chamber with 51 seats; Democrats had the advantage in 48 states, with Ohio filling out the tossup category.

Since then, the topline has remained the same — although Democratic odds have ticked up a touch (our latest model gives them a 25% chance of holding the Senate), Republicans remain favored to win an outright majority. However, there are a number of interesting changes driving the small probability shift under the hood.

Before proceeding, it’s worth taking a look at the state of polling in these Senate races. Split Ticket has built internal polling aggregates for every Senate race that weight for sample size, pollster quality, population, and time. Here’s what our aggregates currently look like at the state level for the nine core “battleground” states at the moment.

As polling frequency increases for a given race, the weight that our model gives to polls also increases; as election day nears, however, the weight assigned to the model’s “fundamentals” shrinks. With the latest polling under our belt, we have ratings changes in five states: Nebraska, Florida, Nevada, Pennsylvania, and Virginia.

Nebraska

We start with Nebraska, a Trump +17 state that most would not expect to see on the board given its strong Republican lean. Why, then, is Deb Fischer’s race now at Likely Republican? There are a few factors to consider.

Last month, Split Ticket partnered with SurveyUSA to conduct a poll of registered voters in the state with a margin of error of ±3.6 points, the results of which you can find here. While the poll predictably showed Trump and Senator Pete Ricketts with commanding leads, it found Deb Fischer ahead by just a single point with a large number of respondents undecided.

Given the uncertainty arising from this unexpectedly good result for Osborn (a former Democrat running as an independent) the model now projects that Fischer has a 92% chance of winning. This is just low enough to drop the race into the Likely Republican column.

It is important to remember that our ratings are assigned probabilistically, rather than on the basis of margin. While the model expects Fischer to eventually win her race by a double-digit margin, the polling average points to a much closer contest. In our model, uncertainty increases as fundamentals diverge from polling.

While we by no means expect Osborn to win (or to even come particularly close to winning) in November, we are committed to consistently applying our methodology across the board. Here, that application yields a race slightly more competitive than expected.

Florida

One new addition to the Leans Republican column is Florida, a state Democrats have recently begun to devote some more attention to. Republican incumbent Rick Scott remains a favorite in his reelection bid against former Democratic Congresswoman Debbie Mucarsel-Powell, but Democrats now have a 25% chance of winning the state, with recent polls showing a fairly close race.

The movement comes as Kamala Harris improves her footing in polls in Florida and Texas, amidst rising numbers with Hispanic voters and minority voters. Given that the map tilts so overwhelmingly against them, Democrats would be well served to allocate additional resources to Florida and Texas, in addition to their defense strategies in Ohio and Montana, to maximize their chances of holding the Senate.

Nevada

In Nevada, a state considered a prime pickup opportunity for Republicans before Biden left the race, Democratic Senator Jacky Rosen is now more comfortably favored to defeat her opponent combat veteran Sam Brown. Rosen maintains a fundraising advantage over Brown and Harris’s general improvements relative to Biden in terms of favorability, particularly among Hispanic and young voters, also help her case. The race is currently Likely Democratic, and while the presidency is anyone’s game right now, we expect Rosen to hold this seat regardless of whether Trump or Harris wins the state.

Pennsylvania

Another minor shift to cover is in Pennsylvania, where a continued barrage of Republican money and advertisements have brought Bob Casey’s polling numbers (and odds) down a touch, from Likely to Leans Democratic, as Democratic odds dip from 81% to 78%.

This represents a slight narrowing of the race. Republicans will want to do better than that, however, given the amount of money that they have pumped in — with $45M in outside expenditures for the race, it is the Senate election they have most heavily invested in. While this has resulted in the polling averages narrowing a bit, Casey still remains the clear favorite, as McCormick has yet to lead in a single publicly-released survey of the race.

Our Senate polling average for the state stands at D+6.6 at the moment, even as Harris leads in Pennsylvania by less than a point. We still expect Casey to win, and our model expects him to comfortably outperform Kamala Harris at this point. But it is likely to be closer than it would have been if Republicans hadn’t decided to invest heavily in this race.

Virginia

One other race that moves off the board completely is Virginia. There really isn’t anything major here to note — Tim Kaine is simply a very strong incumbent in a Biden +10 state that Harris is likely to comfortably win, and he holds a commanding edge in fundraising and polling. No poll shows this race as being competitive, and our model expects him to win handily as well.

The Remainder

The rest of the map is essentially the same. No other candidates’ probabilities of victory have changed enough to shift competitive races into different categories.

The main source of bad news for Democrats comes in Montana, a reliably Republican state where long-time Democratic Senator Jon Tester is running for reelection. Tester has outraised Sheehy but fundamentals are simply not on his side. Biden’s suspension has helped little in a state as favorable to the GOP as Montana, and the model continues to consider the race Leans Republican. A Tester upset is by no means out of the picture (he has just a 26% chance of winning at the moment), but it appears increasingly unlikely.

Democrats Tammy Baldwin (WI), Bob Casey (PA), and Elissa Slotkin (MI) all remain poised to win reelection against their Republican opponents. While we expect polarization to close the gap between the Rust Belt Democratic Senate candidates and Harris, all three are still forecast to outrun the top of the ticket.

In the Sun Belt, Arizona Democrat Ruben Gallego remains favored against his Republican opponent Kari Lake, who has shown no inclination to moderate in a state that is becoming increasingly hostile to her candidacy. Our model finds her chances plummeting over time, with each batch of new polls carrying worse news for her. There is time for this dynamic to reverse, but at the moment, we expect her to lose by over 6 points, which would mark the worst Senatorial performance for an Arizona Republican in decades.

Texas, meanwhile, remains at the border of lean and likely Republican, with Colin Allred having a puncher’s shot in the Lone Star State. The polling we have suggests a close, but Republican-leaning election in the state at the moment, and while we expect Allred to outperform Kamala Harris, it likely won’t be enough, especially as Trump is likely to comfortably win Texas.

Lastly, our model continues to hold the Maryland race at safe Democratic, despite Hogan’s stronger-than-expected polling. A look under the hood justifies this; while Alsobrooks only holds a slender lead in public polling, she also holds an edge in candidate fundraising and is running in a state Harris is likely to win by 30 points. Given that she has now begun to book ad buys, it is likely that Democrats are only going to get stronger from here in a state that leans overwhelmingly to the left.

Ultimately, the story of the cycle is surprisingly clear: Democrats have nominated strong and experienced candidates in a lot of states, but the map is simply too Republican to give them anything more than an outside shot at holding the majority. We’ll see if that holds in our next update in a few weeks.