With Election Day drawing near, Democratic incumbents in key Senate races face growing uncertainty, as new polling suggests a tighter contest than expected. The stakes are high for Democrats, who hold a slim majority in the Senate with 51 seats, including three Independents, against the Republicans’ 49. Out of the 34 Senate seats up for grabs in 2024, 23 are currently held by Democrats or Independents, making the battle for control of the Senate especially crucial.

For Republicans, a net gain of just two seats—or a net gain of one seat combined with a win in the presidential race—could shift the balance of power. The latest polling update indicates intensified competition in Pennsylvania and Nebraska. In Pennsylvania, Democratic Senator Bob Casey is facing unexpected headwinds as the race shifts from “Lean Democrat” to “Toss Up.”

Casey, a three-term incumbent, is up against Republican challenger Dave McCormick, a former hedge fund CEO. McCormick has gained traction recently, turning what was once considered a safer seat for Democrats into one of the nation’s most unpredictable contests. Nebraska, where a special election is underway, also saw a notable shift in Cook’s latest forecast. Although the race was initially expected to lean Republican, the emergence of a strong independent candidate has complicated the landscape.

The Cook Political Report’s revised ratings come as both parties ramp up their efforts to secure these crucial seats. For Democrats, maintaining control of Pennsylvania and other contested seats will be essential to keeping their Senate majority intact. Republicans, meanwhile, see an opportunity to regain power, especially in traditionally red-leaning states.

Harrisburg, PA – October 4, 2016: PA Senator Democrat Bob Casey speaks at a rally for Presidential candidate Hillary Clinton in Harrisburg.

Casey has been making a strategic move ahead of the upcoming election, launching a new TV ad on Friday that aired across parts of the state. In the ad, Casey distances himself from the Biden administration, instead emphasizing his backing of specific Trump-era policies. The ad appears to be a late-game effort to court Trump supporters in the key swing state. A handful of endangered swing-state Democratic U.S. Senate nominees are also starting to cut and run from the Harris campaign, pivoting to praise former President Trump as they seek to protect their own elections.

A review of major TV ads put up by the campaigns of Sen. Bob Casey (D-PA), Rep. Elissa Slotkin (D-MI), and Sen. Tammy Baldwin (D-WI) all portray the former president in a favorable, or at least neutral, light as they signal an openness to work with Trump if he wins in November.

Let’s check in on Democrat Senate candidates in the blue wall states:

Baldwin (WI): Putting Trump in her ads
Casey (PA): Putting Trump in his ads
Slotkin (MI): Making ads against EV mandates.

They wouldn’t be doing this if they thought Kamala was winning. pic.twitter.com/yN1LZTFjXJ

— Greg Price (@greg_price11) October 18, 2024

Cook’s political report referenced McCormick’s efforts “shoring up the GOP base and making gains in the western part of the state,” as a key reason for its analysis. It also highlighted that although Casey leads by several points in public polls, internal polls from both parties suggest the race is within the margin of error. Consequently, Casey’s Senate race is now considered as competitive as those in Michigan, Ohio, and Wisconsin.

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