Overview of the 2020 Senate Election Cycle
Every two years, one-third of the United States Senate is up for election. In 2020, 33 Senate seats were contested, including all 33 Class II and Class III seats and one special seat in Arizona. This was the first midterm cycle after the 2018 midterms and preceded the 2022 cycle. Several factors shaped these races, including the size of the electoral field, primary schedules affected by the COVID-19 pandemic, and national political dynamics. The table below summarizes the 33 seats contested in 2020, showing incumbent presence, party, state, and the winner of each race.
| State | Class | Incumbent (Party) | Election Outcome (Winner) |
|---|---|---|---|
| Alabama | III | Jeff Sessions (R) | Doug Jones (D) |
| Alaska | II | Dan Sullivan (R) | Dan Sullivan (R) |
| Arkansas | II | John Boozman (R) | John Boozman (R) |
| Arizona (special) | III | Appointed (R) | Mark Kelly (D) |
| California | III | Kamala Harris (D) | Kamala Harris (D) |
| Colorado | III | John Hickenlooper (D) | John Hickenlooper (D) |
| Connecticut | III | Richard Blumenthal (D) | Richard Blumenthal (D) |
| Florida | III | Rick Scott (R) | Rick Scott (R) |
| Georgia | II | David Perdue (R) | Jon Ossoff (D) |
| Georgia | III | Kelly Loeffler (R) | Raphael Warnock (D) |
| Iowa | II | Joni Ernst (R) | Joni Ernst (R) |
| Maine | II | Susan Collins (R) | Susan Collins (R) |
| Michigan | II | Gary Peters (D) | Gary Peters (D) |
| Minnesota | II | Tina Smith (DFL) | Tina Smith (DFL) |
| Mississippi | II | Cindy Hyde-Smith (R) | Cindy Hyde-Smith (R) |
| Montana | II | Steve Daines (R) | Steve Daines (R) |
| Nebraska | II | Ben Sasse (R) | Ben Sasse (R) |
| North Carolina | III | Thom Tillis (R) | Thom Tillis (R) |
| North Dakota | III | Kevin Cramer (R) | Kevin Cramer (R) |
| Oregon | II | Jeff Merkley (D) | Jeff Merkley (D) |
| South Carolina | III | Lindsey Graham (R) | Lindsey Graham (R) |
| South Dakota | II | Mike Rounds (R) | Mike Rounds (R) |
| Tennessee | III | Lamar Alexander (R) | Bill Hagerty (R) |
| Texas | II | John Cornyn (R) | John Cornyn (R) |
| Utah | III | Mitt Romney (R) | Mitt Romney (R) |
| West Virginia | II | Shelley Moore Capito (R) | Shelley Moore Capito (R) |
| Wisconsin | III | Tammy Baldwin (D) | Tammy Baldwin (D) |
| Wyoming | II | Mike Enzi (R) | Cynthia Lummis (R) |
What It Means to Be Up for Reelection
Senate terms are staggered so that approximately one-third of the body is elected every two years. The 33 seats contested in 2020 consisted of Class II and Class III seats plus one special election to fill a vacancy. An incumbent senator appears on the general election ballot unless they retire, lose in a primary, or are appointed and not seeking election. Being up for reelection does not guarantee an incumbent’s presence on the ballot; primary losses and retirements can remove incumbents before the general election. The outcomes determine which party controls committee assignments, agenda-setting power, and the ability to confirm presidential appointees.
Notable Outcomes in the 2020 Senate Elections
Several 2020 races shifted the balance of power and received national attention. In Alabama, Democrat Doug Jones defeated incumbent Republican Jeff Sessions, marking a rare pickup in a state that typically votes Republican. In Georgia, both Senate runoffs in January 2021 determined control of the chamber, with Democrats Jon Ossoff and Raphael Warnock winning. In Tennessee, Republican Bill Hagerty succeeded retiring Lamar Alexander. These changes affected committee leadership, judicial confirmations, and legislative maneuvering for the remainder of the 116th Congress and into the 117th.
Post-Election Changes and Impact
After the 2020 elections, party control of the Senate shifted following the January 2021 Georgia runoff elections. These outcomes influenced presidential appointment confirmations, budget reconciliation usage, and the progression of major legislative initiatives. Several senators who were up in 2020 chose not to seek reelection in subsequent cycles, reshaping the political landscape for 2022 and beyond. Understanding which senators were up for reelection in 2020 and how they fated provides necessary context for interpreting Senate composition and policy output in that period.
Definitions and Key Terms
- Class II Senate seats: One of three groups of Senate seats assigned to stagger terms so roughly one-third of the Senate is elected every two years.
- Special election: An election held to fill a Senate vacancy that occurs between regularly scheduled elections.
- Incumbent: The current officeholder seeking reelection in a given cycle.
- Runoff election: A second election held when no candidate receives a majority of votes in the initial general election, used in Georgia for Senate races.
Context and Relevance
The 2020 Senate elections occurred alongside a contentious presidential election and a global pandemic, affecting campaign tactics, voter turnout, and Senate priorities. Control of the chamber influenced the ability to pass legislation and confirm judges and executive branch nominees. For historical and analytical purposes, knowing which senators were up for reelection in 2020 and the results helps explain subsequent Senate actions and membership changes through 2021 and beyond.