Democrats are defending a slim Senate majority. Here’s a look at the states where both parties are fighting for control.

• The 2024 Senate elections — which will run concurrent with the presidential race — are approaching.
• Democrats will have to defend several vulnerable incumbents in swing and GOP-heavy states.
• However, the party has held its own in the last three cycles in navigating tough Senate races.

In the 2022 midterm elections, Democrats defied political expectations by holding on to their Senate majority. Every incumbent secured reelection, and then-Pennsylvania Lt. Gov. John Fetterman flipped the seat vacated by retiring Republican Sen. Pat Toomey.

The upper chamber in January 2023 then shifted from its previous 50-50 split — with Senate control in 2021 and 2022 resting on Vice President Kamala Harris’ tiebreaking abilities — to a 51-49 majority led by Majority Leader Chuck Schumer of New York. And despite Arizona Sen. Kyrsten Sinema a fourth term in 2024.

Casey — a former Pennsylvania auditor general and ex-state treasurer who has won all three of his prior Senate races with relative ease — will likely benefit from running in a presidential year when turnout in the Democratic strongholds of Philadelphia and Pittsburgh is poised to be very high.

However, Casey has also generally done well in many of the state’s working-class towns and cities, and he could post an electoral performance similar to Fetterman, who dominated in the vote-rich Philadelphia suburbs in 2022.

David McCormick, a businessman who narrowly lost the 2022 Republican Senate primary to Dr. Mehmet Oz, will be the party’s Senate nominee in the fall. McCormick, who grew up in the Pittsburgh area, is viewed as a candidate who can potentially bolster the GOP among Independents and suburban voters.

Wisconsin

Sen. Tammy Baldwin in August 2024 won the Democratic primary in her bid for a third term.

While Wisconsin in recent years has been one of the most politically polarized states in the country, Baldwin was able to win over many rural and exurban voters during her 2012 and 2018 campaigns — while also racking up large margins in the Democratic-heavy population centers of Milwaukee and Madison.

Businessman Eric Hovde won the GOP primary, defeating construction worker Charles Barman and Rejani Raveendran, the chair of the University of Wisconsin-Stevens Point College Republicans.

Several of the most prominent Republicans who were thought of as potential candidates — including former Gov. Scott Walker, Reps. Bryan Steil and Tom Tiffany, and former Rep. Mike Gallagher — declined to enter the race.