The 2024 United States Senate election in Pennsylvania was held on November 5, 2024, to elect a member of the United States Senate to represent the state of Pennsylvania. Republican businessman Dave McCormick won his first term in office, defeating Democratic three-term incumbent Bob Casey Jr. in what was considered a major upset. Most predictions gave Casey a slight advantage, and he led in most polls. Along with Sherrod Brown in Ohio and Jon Tester in Montana, Casey was one of three incumbent senators to lose re-election in 2024, all of whom were Democrats first elected in 2006.
The primary election took place on April 23, 2024. The election was considered essential for Democrats' chances to retain their majority in 2024. The Associated Press and Fox News declared McCormick the winner on November 7, while Decision Desk HQ called the race for McCormick on November 14. CNN, NBC, ABC, and CBS all called the race for McCormick on November 21; Casey conceded the race later that day, halted a recount and confirmed the result.
This was Pennsylvania's closest US Senate election since the passage of the Seventeenth Amendment, as well as the closest Senate election of the 2024 cycle. McCormick was the only Republican challenger to win in a state flipped by Trump in the 2024 presidential election. The other three Republican Senate gains were in states Trump had won in all three of his runs. With Democrats flipping the other Senate seat two years earlier, this was the first time since the 2012 Senate election in Indiana where the opposite party flipped a seat after losing one in the previous cycle.
This was Casey's first general election loss of his political career, and the second counting Casey's primary election loss in 2002. This election made Pennsylvania one of several states to have a younger senior senator (John Fetterman) and an older junior senator (McCormick). McCormick was sworn in on January 3, 2025.
Background Pennsylvania is considered to be a purple state at the federal level, especially since in the 2020 presidential election, Joe Biden carried Pennsylvania by about 1.2 percentage points. Democrats had controlled both U.S. Senate seats, the governorship, a majority of its U.S. House delegation, and the Pennsylvania House of Representatives. The last time Republicans won a U.S. Senate seat in Pennsylvania was in 2016.
Senator Bob Casey Jr. was first elected in the blue wave of 2006, defeating then-incumbent Senator Rick Santorum by about 17 percentage points. He was re-elected in 2012 by 9 percentage points (when he ran ahead of Obama by almost 4 points) and in the blue wave of 2018 by 13 percentage points. Given these three decisive victories, Casey's fourth term appeared inevitable for much of the race. However, tightening polls in the final weeks indicated a closer contest, even as Casey was largely considered the favorite to win.
Democratic primary Candidates Nominee Bob Casey Jr., incumbent U.S. senator (2007–2025)
Disqualified William Parker, app developer
Endorsements
Fundraising Campaign finance reports as of April 15, 2024CandidateRaisedSpentCash on handBob Casey Jr. (D)$23,790,263$12,391,802$11,886,480Source: Federal Election Commission
Results
Republican primary Candidates Nominee Dave McCormick, former U.S. Under Secretary of the Treasury for International Affairs (2007–2009), former CEO of Bridgewater Associates (2020–2022), and candidate for U.S. Senate in 2022
Withdrawn Brandi Tomasetti, former Conestoga Township treasurer and secretary (ran as a write-in candidate)
Disqualified Joseph Vodvarka, spring manufacturer and perennial candidate
Declined Kathy Barnette, political commentator, nominee for in 2020, and candidate for U.S. Senate in 2022 Stacy Garrity, Pennsylvania State Treasurer (2021–present) (running for re-election) Doug Mastriano, state senator for SD-33 (2019–present) and nominee for Governor of Pennsylvania in 2022 (endorsed McCormick)
Endorsements
Fundraising Campaign finance reports as of April 15, 2024CandidateRaisedSpentCash on hand Dave McCormick (R)$11,052,879$4,660,701$6,399,998Source: Federal Election Commission
Polling
Poll source Date(s)administered Samplesize Marginof error KathyBarnette DougMastriano DavidMcCormick UndecidedPublic Policy Polling (D)Public Policy Polling (D)March 9–10, 2023616 (LV)–11%39%21%29%––42%28%29%
Results
Third parties Libertarian convention Nominee John Thomas, educator
Eliminated at convention Erik Gerhardt, carpenter, nominee for U.S. Senate in 2022, and candidate for president in 2020
Green Party Nominee Leila Hazou, shop owner
Constitution Party Nominee Bernard Selker, truck driver
American Solidarity Party Disqualified Erik Messina
General election Predictions SourceRankingAs of The Cook Political Report October 21, 2024 Inside Elections November 9, 2023 Sabato's Crystal Ball June 13, 2024 Decision Desk HQ/The Hill June 8, 2024 Elections Daily October 24, 2024 CNalysis November 21, 2023 RealClearPolitics August 5, 2024 Split Ticket October 23, 2024 538 October 28, 2024
Post-primary endorsements
Fundraising Campaign finance reports as of October 16, 2024CandidateRaisedSpentCash on handBob Casey (D)$52,879,737$50,545,793$2,821,961Dave McCormick (R)$27,698,652$26,030,736$1,675,736Source: Federal Election Commission
Debates + 2024 Pennsylvania U.S. Senate election debates Date Host Moderator Link Democratic RepublicanKey: Participant Absent Not invited Invited Withdrawn Casey McCormick1 October 3, 2024 WHTM-TV Dennis Owens YouTube 2 October 15, 2024 WPVI-TV Matt O'Donnell, Sharrie Williams, Ilia Garcia C-SPAN
Polling Aggregate polls Source of pollaggregationDatesadministeredDatesupdated BobCasey Jr. (D) DaveMcCormick (R) UndecidedMargin538through November 4, 2024November 4, 202448.2%45.4%6.4%Casey +2.8%RealClearPoliticsOctober 21 – November 4, 2024November 4, 202448.1%46.3%5.6%Casey +1.8%270toWinOctober 24 – November 4, 2024November 4, 202448.4%45.9%5.7%Casey +2.5%TheHill/DDHQthrough November 4, 2024November 4, 202448.6%46.6%4.8%Casey +2.0%Average48.3%46.1%5.6%Casey +2.2%