Closest U.S. Senate elections in Pennsylvania
The closest U.S. Senate election in Pennsylvania history was in 2024, a margin of 0.22 points. Dave McCormick beat Robert P. Casey Jr., 3,399,295 to 3,384,180. Next closest are 1956 (0.39 points) and 1944 (0.64 points).
Every state is ranked together on Closest U.S. Senate elections in history. For every Senate race Pennsylvania has held, special elections included, see the Pennsylvania U.S. Senate hub.
What is the closest Senate race in Pennsylvania history?
The Pennsylvania Senate election decided by the narrowest margin was in 2024, 0.22 points. Dave McCormick beat Robert P. Casey Jr., 3,399,295 to 3,384,180. The next closest were 1956 (0.39 points) and 1944 (0.64 points).
How is the margin measured?
As the gap in vote share between the first and second-place finishers, from the certified general-election count. It is not adjusted for recounts, runoffs or later court rulings; the figure is the result as certified.
Does this include special elections?
No. These are the regular general elections for Pennsylvania’s two Senate seats. Special elections to fill a vacancy appear on the Pennsylvania Senate hub, which lists every race including specials, and in a few states one of those is closer than anything here.
Why does the list start in 1914?
Because senators were chosen by state legislatures before the Seventeenth Amendment. 1914 is the first cycle of the popular-vote era for the Senate, so it is the first Pennsylvania election with a popular margin to measure.
| # | Election | Result | Votes | Margin |
|---|---|---|---|---|
| 1 | 2024 | Dave McCormick R def. Robert P. Casey Jr. D | 3,399,295 – 3,384,180 | 0.22 points |
| 2 | 1956 | Joseph S. Clark D def. James H. Duff R | 2,268,641 – 2,250,671 | 0.39 points |
| 3 | 1944 | Francis J. Myers D def. James J. Davis R | 1,864,735 – 1,840,943 | 0.64 points |
| 4 | 2016 | Patrick J. Toomey R def. Katie McGinty D | 2,951,702 – 2,865,012 | 1.4 points |
| 5 | 1964 | Hugh Scott R def. Genevieve Blatt D | 2,429,858 – 2,359,223 | 1.5 points |
| 6 | 2010 | Patrick J. Toomey R def. Joe Sestak D | 2,028,945 – 1,948,716 | 2.0 points |
| 7 | 1962 | Joseph S. Clark D def. James E. Van Zandt R | 2,238,383 – 2,134,649 | 2.4 points |
| 8 | 1980 | Arlen Specter R def. Pete Flaherty D | 2,230,404 – 2,122,391 | 2.4 points |
| 9 | 1994 | Rick Santorum R def. Harris Wofford D | 1,735,691 – 1,648,481 | 2.5 points |
| 10 | 1992 | Arlen Specter R def. Lynn Yeakel D | 2,358,125 – 2,224,966 | 2.8 points |
| 11 | 1958 | Hugh Scott R def. George M. Leader D | 2,042,586 – 1,929,821 | 2.8 points |
| 12 | 1950 | James H. Duff R def. Francis J. Myers D | 1,820,400 – 1,694,076 | 3.6 points |
| 13 | 1952 | Edward Martin R def. Guy K. Bard D | 2,331,034 – 2,168,546 | 3.6 points |
| 14 | 1934 | Joseph F. Guffey D def. David A. Reed R | 1,494,010 – 1,366,872 | 4.3 points |
| 15 | 1940 | Joseph F. Guffey D def. Jay Cooke R | 2,069,980 – 1,893,104 | 4.4 points |
| 16 | 2022 | John K Fetterman D def. Mehmet C Oz R | 2,751,012 – 2,487,260 | 4.9 points |
| 17 | 1976 | H. John Heinz III R def. William J. Green D | 2,381,891 – 2,126,977 | 5.6 points |
| 18 | 1970 | Hugh Scott R def. William G. Sesler D | 1,874,106 – 1,653,774 | 6.0 points |
| 19 | 1968 | Richard S. Schweiker R def. Joseph S. Clark D | 2,399,762 – 2,117,662 | 6.1 points |
| 20 | 1932 | James J. Davis R def. Lawrence H. Rupp D | 1,375,549 – 1,200,767 | 6.3 points |
| 21 | 2000 | Rick Santorum R def. Ron Klink D | 2,481,962 – 2,154,908 | 6.9 points |
| 22 | 1974 | Richard S. Schweiker R def. Peter Flaherty D | 1,843,317 – 1,596,121 | 7.1 points |
| 23 | 2012 | Robert P. Casey Jr. D def. Tom Smith R | 3,021,364 – 2,509,132 | 9.1 points |
| 24 | 1938 | James J. Davis R def. George H. Earle D | 2,086,932 – 1,694,464 | 10.3 points |
| 25 | 2004 | Arlen Specter R def. Joseph M. Hoeffel D | 2,925,080 – 2,334,126 | 10.6 points |