ANALYSIS — Republicans failed to take control of the Senate in 2022, but they’ll have another good shot at it in 2024. 

This year was a tremendous opportunity for the GOP. Republicans got to run in a midterm election with an unpopular Democratic president as voters were concerned about the health of the economy and direction of the country. Republicans needed a net gain of just a single Senate seat for a majority. And yet they fell short. 

With the Georgia runoff in the books, Democrats gained a seat in 2022, pushing their Senate majority to 51-49. While control of the Senate was already decided when Democrats won critical races in Nevada and Pennsylvania in November, Sen. Raphael Warnock’s victory Tuesday in Georgia provides a much-needed bulwark as Democrats attempt to hold on to their majority in two years.

The big picture

At the outset, the field of Senate seats is tilted in Republicans’ favor with a disproportionate number of vulnerable Democratic seats. Twenty-one Democrats (and two independents who caucus with Democrats) are up for reelection in 2024, compared with just 11 Republicans. It’s Class I, for any congressional nerds keeping track at home, plus the soon-to-be-vacant Nebraska seat of Republican Sen. Ben Sasse. 

The disparity in party control of the seats in this group goes back to 2006, when Democrats gained six Senate seats (and the majority) in President George W. Bush’s second midterm election. Democrats gained another two seats in this class in 2012, when President Barack Obama won reelection. Republicans gained back two seats in this class in 2018 during President Donald Trump’s midterm election, but the disparity remains. 

The partisanship of the states within the class are particularly challenging for Democrats. Three Democratic senators will have to run for reelection in states Trump won in 2020: Joe Manchin of West Virginia, Sherrod Brown of Ohio, and Jon Tester of Montana. Five more Democrats whose seats are up for reelection represent states Joe Biden won narrowly: Kyrsten Sinema of Arizona, Tammy Baldwin of Wisconsin, Jacky Rosen of Nevada, Bob Casey of Pennsylvania and Debbie Stabenow of Michigan. 

There are no Republican senators up for reelection in 2024 in states that Biden won. That’s significant considering just one state (Wisconsin) voted the opposite way for the Senate in 2022 compared with 2020.

Looking at the initial 2024 Senate map, the most vulnerable Republican incumbent appears to be Rick Scott of Florida, where GOP Gov. Ron DeSantis was just reelected by 19 points and GOP Sen. Marco Rubio won another term by 17 points. Florida hasn’t been a swing state for a while, and after 2022, it isn’t even a battleground state anymore. 

Baseline

Inside Elections’ Baseline captures a state’s political performance by combining all federal and state election results over the past four election cycles into a single score (a trimmed mean, to be specific). It seeks to approximate what share of the vote the “typical” Democrat or Republican might receive in any given state, showing major trends that have emerged over the past few election cycles.

Following the 2022 elections, Republicans have an advantage of 53.9 percent to Democrats’ 45.1 percent in Florida, according to Baseline. That 8.8-point difference is in Democrats’ best initial takeover opportunity in 2024 and is daunting compared with the states Democrats are defending. At this point, a Democratic win in Florida is about as likely as a Republican win in Colorado.

Republicans have a Baseline advantage in West Virginia (21.5 points), Montana (11.7 points), Ohio (11.2 points) and Arizona (1.8 points), all states with a Democratic incumbent. And Democrats are defending six more states (Wisconsin, Nevada, Pennsylvania, Michigan, Virginia and Minnesota) where they have a more narrow Baseline advantage than Republicans have in Florida.

In 2022, just three races broke against the state’s Baseline partisanship. Democratic Sen. Raphael Warnock won reelection in Georgia, where Republicans have a 4.5-point edge. GOP Sen. Ron Johnson won in Wisconsin, where Democrats have a 1-point edge. And Democratic Sen. Mark Kelly won in Arizona, where Republicans still have a 1.8-point advantage.

The senators

Strong incumbents and flawed GOP challengers fueled Democrats’ success in 2022. Democrats will need to follow the same blueprint again in 2024, but it won’t be easy. 

Manchin has proven he can win in a difficult state, but West Virginia has changed. In 2018, the last time the senator was on the ballot, Republicans had a 5.8-point advantage in the Mountain State, according to Baseline. After the 2022 elections, that GOP advantage has stretched to 21.5 points. 

Montana saw a less dramatic shift, from 6.6 points after 2018 to 11.7 after 2022. Ohio has barely moved (R+9.6 post-2018 and R+11.2 post-2022) but remains a challenge for Democrats, as Democratic Rep. Tim Ryan’s nearly 7-point loss in the Senate race last month to Republican J.D. Vance shows. All of those Baselines are more than twice the partisan disadvantage Warnock just overcame in Georgia.

Baldwin and Rosen face reelection in habitual swing states. Democrats have just a 1-point edge in Wisconsin and 1.7-point advantage in Nevada, according to Baseline. Despite recent Democratic success, Republicans still have a 1.8-point advantage in Arizona. But primaries on both sides of the aisle — Sinema is almost certain to face a progressive challenger — add an extra level of volatility to that race. 

Casey, Stabenow and even Democratic Sen. Tim Kaine of Virginia start the cycle in a stronger position but can’t take their races for granted. Their electoral fates could be partially dictated by the national political environment, presidential nominees and strength of their own challengers.

Democrats might try to make noise against GOP Sen. Ted Cruz, but Texas has proven to be stubbornly red. It shifted a bit from the 14.5-point GOP edge after 2018, when Democrat Beto O’Rourke was a fresh statewide face challenging Cruz, to a 10.8-point advantage for Republicans after 2022. At this point, a statewide Democratic win in Texas is about as likely to happen as a Republican win in New Mexico.

The battlefield

The initial 2024 Senate battlefield could consist entirely of seats currently held by Democrats. It’s hard to remember the last cycle in which that occurred. Even when the battlefield is slanted, the other party is usually playing some defense. 

West Virginia, Montana, Ohio, Arizona, Wisconsin, Nevada, Pennsylvania, Michigan and Virginia are all vulnerable to some degree, while Florida is on the outside looking in.

Even without knowing the political environment and presidential nominees, Republicans start the 2024 cycle with a great opportunity to take back the Senate majority. But the GOP has shown that opportunity isn’t enough to get control of the chamber. 

Nathan L. Gonzales is an elections analyst with CQ Roll Call.