Iowa’s roughly 13-point vote for Donald Trump in 2024 raises a historical question about a potential Democratic Senate pickup. Trump won both Iowa and the presidency. The relevant comparison is therefore an opposition party taking a Senate seat from the president’s party in a state the president carried comfortably two years earlier.
This paper examines that outcome across the 12 completed midterm cycles from 1978 through 2022, separating open-seat victories from defeats of sitting senators. It excludes New Jersey in 1982 because that seat’s temporary Republican control resulted from an appointment replacing a Democratic senator.
The Question
Over the last 50 years, how often did a candidate win the presidency and carry a state by at least 13 percentage points, only for the opposing party to capture one of that state’s Senate seats from the president’s party in the midterm election two years later? How many victories involved open seats, and how many involved defeating an incumbent?
The Answer
Twelve Senate seats changed parties under these conditions: nine Republican seats were won by Democrats, and three Democratic seats were won by Republicans. Two involved open seats, and 10 involved defeating sitting senators.
Among the nine Democratic pickups, one involved an open seat and eight involved defeating incumbents. Among the three Republican pickups, one involved an open seat and two involved defeating incumbents.
Eight of the 12 qualifying pickups—66.7 percent—occurred during Ronald Reagan’s presidency. Seven occurred in 1986 alone. Most precedents therefore come from elections held at least 40 years before the 2026 midterms.
Only four occurred after the Reagan years: Illinois in 1998, Montana in 2006, and Illinois and Wisconsin in 2010. None occurred in the 2014, 2018 or 2022 midterms.
The Two Open-Seat Pickups
Nevada, 1986: Democrat Harry Reid won the seat vacated by retiring Republican Paul Laxalt after Reagan carried Nevada by 33.88 percentage points in 1984—a Republican-to-Democratic pickup. This was the largest preceding presidential margin overcome by any qualifying pickup.
Illinois, 2010: Republican Mark Kirk defeated Democrat Alexi Giannoulias for the seat held by departing Democratic appointee Roland Burris after Obama carried Illinois by 25.14 points in 2008—a Democratic-to-Republican pickup. Burris had replaced Obama and did not seek election. This counts because the seat changed from Democratic to Republican control both relative to its appointed occupant and relative to the party that had last won it in an election.
The 10 Victories Over Sitting Senators
New Mexico, 1982: Democrat Jeff Bingaman defeated Republican Harrison Schmitt after Reagan carried the state by 18.20 points in 1980—a Republican-to-Democratic pickup.
Alabama, 1986: Democrat Richard Shelby defeated Republican Jeremiah Denton after Reagan carried the state by 22.26 points in 1984—a Republican-to-Democratic pickup.
Florida, 1986: Democrat Bob Graham defeated Republican Paula Hawkins after Reagan carried the state by 30.66 points in 1984—a Republican-to-Democratic pickup.
Georgia, 1986: Democrat Wyche Fowler defeated Republican Mack Mattingly after Reagan carried the state by 20.39 points in 1984—a Republican-to-Democratic pickup.
North Carolina, 1986: Democrat Terry Sanford defeated Republican Jim Broyhill after Reagan carried the state by 24.00 points in 1984—a Republican-to-Democratic pickup.
North Dakota, 1986: Democrat Kent Conrad defeated Republican Mark Andrews after Reagan carried the state by 31.04 points in 1984—a Republican-to-Democratic pickup.
South Dakota, 1986: Democrat Tom Daschle defeated Republican James Abdnor after Reagan carried the state by 26.47 points in 1984—a Republican-to-Democratic pickup.
Illinois, 1998: Republican Peter Fitzgerald defeated Democrat Carol Moseley Braun after Bill Clinton carried the state by 17.51 points in 1996—a Democratic-to-Republican pickup.
Montana, 2006: Democrat Jon Tester defeated Republican Conrad Burns after George W. Bush carried the state by 20.50 points in 2004—a Republican-to-Democratic pickup.
Wisconsin, 2010: Republican Ron Johnson defeated Democrat Russ Feingold after Obama carried the state by 13.91 points in 2008—a Democratic-to-Republican pickup.
Broyhill requires a qualification: he was an appointed incumbent who replaced Republican John East shortly before the election. He had already won the Republican nomination and then contested the general election. Sanford’s victory counts as defeating a sitting senator, although Broyhill had never won election to the Senate. The other nine defeated incumbents had previously won election to their seats.
Why New Jersey in 1982 Is Excluded
Democrat Frank Lautenberg defeated Republican nominee Millicent Fenwick after Reagan carried New Jersey by 13.42 points in 1980. Republican Nicholas Brady temporarily held the Senate seat but did not run. Brady had replaced Democrat Harrison Williams, so the apparent Republican-to-Democratic pickup followed an appointment that had temporarily changed the seat’s party. The election returned the seat to the party that had last won it at the ballot box. Excluding this case leaves 12 qualifying pickups.
Approximately 3 Percent of Midterm Senate Races
Across the 12 midterm elections from 1978 through 2022, an estimated 400 regular Senate races were held. Twelve produced opposition-party pickups in states the president had carried by at least 13 percentage points two years earlier—approximately 3 percent of all regular Senate contests, or one in 33. This is an estimate based on roughly 33 races per midterm; it does not count special elections separately. The percentage measures how frequently this outcome occurred among all Senate races, rather than the success rate among challenges meeting these specific conditions.
What This Means for Iowa
A Democratic Senate victory in Iowa would have historical precedents, but the closest ones are old. The only comparable Democratic open-seat pickup was Harry Reid’s Nevada victory in 1986. Illinois in 2010 provides a more recent open-seat example in the opposite partisan direction.
The most recent comparable Democratic pickup of either kind was Jon Tester’s defeat of Conrad Burns in 2006. A Democratic victory in Iowa would therefore be the first qualifying Democratic pickup in 20 years.
This history supports describing an Iowa Democratic pickup as unusual, especially in the modern period. It does not establish that a forecast predicting one is wrong.
Eight of the 12 precedents came during the Reagan years, making their age and concentration as important as their number.
Scope and Sources
The analysis covers midterm general elections and associated runoffs from 1978 through 2022. The president must have carried the state by at least 13 percentage points two years earlier, and the Senate seat must have changed from the president’s party to the opposing party. Presidential margins use all votes cast, rather than the two-party vote. Each seat is counted once; party switches and transitions involving independents are excluded.
Sources include statewide presidential returns compiled by the American Presidency Project, Senate election summaries, and Brookings’ compilation of Senate seats changing parties. Counts, percentages and classifications are calculations for this paper.
Author’s Note: I am gradually moving all explicitly political material to Medium; my finance and economics articles will remain on Substack. Follow me at Medium.
Some political articles already available on Medium include:
· A Resident’s Guide to Colorado Politics.
· My assessment of three structural forces shaping the battle for House control.
· My discussion of two sleeper races in Minnesota.
· My assessment of the closely watched Senate and House contests in Maine.