Not a toss-up?

Last night, I released the Senate forecast for November, and it opened with a number that may be shocking to casual political observers: Republicans have a 100% chance of winning the Senate this November.

Now, it's not quite 100%. The crystal ball does do some rounding, but in 10,000 simulations, Democrats won the Senate just 1 time. And only tied Republicans for control of the Senate in just 10 of those simulations.

To understand how this is even possible, we need to first take a look at the current makeup of the Senate. Democrats hold 51 seats while Republicans hold 49. That means by flipping just two seats, Republicans would wrest control of the upper chamber from the Dems.

We need to also look at the seats that are actually up for election this year. This matters because, unlike the House which holds elections for all seats every 2 years, the Senate holds elections for a third of the chamber every 2 years. This year, Democrats have 23 seats they are fighting to hang on to; Republicans only have 10. What's more, in the swing states that actually have a Senate race this year, all of them are currently held by a Democrat. This includes Pennsylvania, Michigan, Wisconsin, Arizona¹, and Nevada.

Understandably, all of these seats will be close this fall, in large part because the presidential race will be there also, which means that these seats could really swing either way. But how can we be so confident that Republicans are going to flip the Senate? Afterall, many of those states could reasonably be considered as 60-40 toss-ups favoring the Democrat as the race stands today.

Well, in another election cycle, Democrats could play more offensively and go after the Republican incumbents in Texas and Florida -- the two most vulnerable Republican seats (which aren't exactly close). But with so many incumbents up for election in critical states, Democrats are stuck playing defense. That means Republicans are very likely to not cede a single seat to the Dems this fall, so they start out already knowing they have got 49 seats in the bag.

Bleeding in Deep Red States

But the biggest issue for Democrats isn't the races in the swing states, however. The biggest issue is the races going on in the "safe" states. Specifically, the races for the three seats they hold in the deep red states of Montana, West Virginia, and (to a lesser extent) Ohio.

Joe Manchin (D-West Virginia) is retiring, and popular West Virginia governor Jim Justice (R) is running for his seat. Being the second most Trump-friendly state in the country, West Virginia is a safe flip for the Republicans, already bringing their total to a minimum of 50 seats. That will be enough for Republicans to pass legislation with the help of a tie-breaking vote from J.D. Vance should the ticket win the White House this November.

Montana has elected John Tester (D) to represent them three times starting with his first run in 2006, but his time looks to have run out. After voting with the Biden-Harris administration 91% of the time, the state of Montana is poised to send Tester packing and replace him with Tim Sheehy (R). Sheehy, a Navy SEAL veteran, now leads in polling by upper single digits. Sheehy's margin likely rises on election day as Trump is expected to carry the state between 15 and 20%. With this flip, Republicans would hold 51 seats and a simple majority.

Ohio, along with Florida, was once considered the prototypical swing state, but in the age of MAGA, it realigned itself as a dependable Republican state. Just two years ago, the Buckeye State sent a political newcomer J.D. Vance to the Senate over a popular Democratic House member Tim Ryan. It was not until that October that J.D. began to show a lead in the polling. For most of that cycle, Ohio polling showed Ryan cruising to a victory. Flash forward to today, and we're seeing the same phenomenon. Bernie Moreno (R) currently trails incumbent Sherrod Brown (D) by mid-single digits.

Unfortunately for Brown, one of the biggest factors for how someone votes for senator is how they vote for president.² Voters just do not split their tickets that much anymore. Considering that, the forecast model puts Brown's odds at less than 5% in a state where Trump is expected to carry the state between 8 and 11% percent. If Moreno should prevail over the incumbent, that would give Republicans 52 seats.

A Chance to Rebound in the Southwest

Due to the fact that so few people split their tickets anymore, the forecast currently gives Kari Lake (R) a 77% chance of fulfilling her political redemption arc. Lake, as you might remember, came up just short in a gubernatorial race two years ago.

Frankly, this one may end up coming back to bite me. Senate polling plays an important but not hugely deterministic role in determining a state's senate forecast. The forecast is largely predicated on the statistical relationship between how a state votes for president and how it votes for senators in the same election, with the belief that your choice for president largely informs your vote for senate regardless of who runs in that senate race. In fact, those numbers have, as of late, largely fallen in line. If you want a representation of what this looks like, I posted this on X; it shows the positive statistical relationship between a state's presidential margin and its senate margin.

Still, Arizona presents an opportunity for a big miss. A lot of the polls have her down by low- to mid-single digits, but there have been polls that show an almost unthinkable blow out -- D+15% from Fox! She made a name for herself in 2022 and became a polarizing figure in the process. With that said, she narrowly lost that race, and it was against a less divisive opponent. I do think the forecast is too bullish on her, but if Trump wins the state of Arizona by the margin he currently holds (4-5%), I would expect Lake to eke out a win of less than 2%. 53 seats?

Neighboring Nevada has far more routinely shown signs of a blowout despite Trump leading in the state. Nevada last elected a Republican senator in 2012 -- Dean Heller. Jackie Rosen, the current seat holder, booted him from his spot in 2018 by a 5% margin. That is 4.5% to the left of where the national margin was that year -- D+8.6%. I say that because by the time the U.S. held its next midterm, Nevada actually voted to the right of the country. That's not an outlier for the state either.

In each of the past three presidential elections, Nevada has moved 2.4% to the right, relative to the rest of the country. It has moved so much so that it voted more conservatively in 2020 than it did in 2016. Looking at the down ballot races and at the top of the ticket, Nevada has shown an increasing tendency to vote for the Republican Party. That is why I have a hard if not impossible time believing that an Afghanistan veteran and Purple Heart recipient Sam Brown (R) could be losing by double digits to a not-so-popular incumbent. Based on feel alone, this race seems much easier for Republicans to flip than Arizona, but that feeling is not currently supported by the polling.

The forecast currently gives Brown the edge in what it considers to be a toss-up race. A narrow loss here would not surprise me, but if Trump carries the state by 3%, Brown should eke out a win here. 54 seats... ?

Opportunities in the Midwest

The last three seats of any serious consideration are the senate races in Michigan, Wisconsin, and Pennsylvania. All three of which actually have much closer polling than the two aforementioned seats in the southwest. With polling routinely showing a race in the low single digits, one might expect whichever party wins at the top of the ticket also wins at the senate level.

While voters largely do not split their tickets anymore, enough of them do that even in a case where Trump wins all three states by 1-2%, the three Democratic senate candidates could still prevail. Wisconsin and Pennsylvania both have Democratic incumbents in the race, which just makes it that much harder for the seat to be flipped. Michigan, however, does not, but of the three states, it has most consistently polled as the bluest and does, in fact, tend to vote the most to the left out of the three.

On a good night for Trump, all three could flip, bringing the total Republicans seats to a high watermark of 57. On an average night, however, I would expect no changes here. It really depends on how much Trump wins these states by. Should he lose any of them, that seat simply will not flip. These seats are all "Lean Dem" right now largely because of the narrow lead Harris does hold over Trump in these three states. But, if recent history serves as any indication, Trump -- and by extension his senate hopefuls -- may outperform the polls in the Midwest once again.