1920 United States Senate elections

The 1920 United States Senate elections were elections for the United States Senate that coincided with the presidential election of Warren G. Harding. The 32 seats of Class 3 were contested in regular elections, and special elections were held to fill vacancies. Democrat Woodrow Wilson's unpopularity allowed Republicans to win races across the country, winning ten seats from the Democrats and providing them with an overwhelming 59-to-37 majority. The Republican landslide was so vast that Democrats lost over half of the contested seats this year and failed to win a single race outside the South. In fact, this is the most recent occasion where every race decided by under 10 points all voted for the same party, showcasing the sheer strength of Republicans' performance in this election.

Since the passage of the Seventeenth Amendment, these elections were the closest in which the winning party in almost every Senate election mirrored the winning party for their state in the presidential election, with Kentucky being the only Senate race not to mirror their presidential result. No other Senate election cycle in a presidential year would come close to repeating this feat until 2016, in which the result of every Senate race mirrored the corresponding state's result in the presidential election. Coincidentally, that election cycle involved the same class of Senate seats, Class 3. This is also one of only five occasions where 10 or more Senate seats changed party in an election, with the other occasions being in 1932, 1946, 1958, and 1980.

, the 59 seats held after this election cycle remains the highest number of seats that the Republican Party has held as the result of an election cycle. This number rose to 60, the highest number of seats the Republicans have ever held, after Democrat senator Josiah O. Wolcott of Delaware accepted an offer from Republican governor William D. Denney to become Chancellor of the Delaware Court of Chancery, allowing Denney to name Republican T. Coleman du Pont to replace Wolcott, a seat du Pont held until the next election, in which both a special election was held for the remainder of the term and a regular election was held as the seat was normally up then, both of which du Pont lost narrowly to Democrat Thomas F. Bayard Jr. In addition, the 22-seat majority is the largest majority that the Republicans have achieved in any election since.

Gains, losses, and holds

Retirements

Two Republicans and three Democrats retired instead of seeking re-election. One Democrat retired instead of seeking election to finish the unexpired term.

{| class="wikitable sortable plainrowheaders"

! scope="col" |State

! scope="col" |Senator

! scope="col" |Replaced by

! Alabama (special)

| |

! Colorado

| |

! Illinois

| |

! Louisiana

| |

! Ohio

| |

! South Dakota

| |

Defeats

Ten Democrats and one Republican sought re-election but lost in the primary or general election.

{| class="wikitable sortable plainrowheaders"

! scope="col" |State

! scope="col" |Senator

! scope="col" |Replaced by

! Arizona

| |

! Arkansas

| |

! California

| |

! Georgia

| |

! Idaho

| |

! Kentucky

| |

! Maryland

| |

! Nevada

| |

! North Dakota

| |

! Oklahoma

| |

! Oregon

| |

Post-election changes

{| class="wikitable sortable plainrowheaders"

! scope="col" |State

! scope="col" |Senator

! scope="col" |Replaced by

! Delaware

| |

! New Mexico

| |

! Georgia

| |

! Pennsylvania (class 1)

| |

! Pennsylvania (class 1)

| |

! Pennsylvania (class 3)

| |

! Iowa

| |

! Michigan

| |

Change in composition

Before the elections

{| class="wikitable" style="text-align:center" width=800px

| colspan=2 |  

| | D

| width=50px | D

| | D

| | D

| rowspan=2 | R

| colspan=9 align=right | Majority →

| | R

| | R

| colspan=2 |

| | R

Election results

{| class="wikitable" style="text-align:center" width=800px

| colspan=2 |  

| | D

| width=50px | D

| | D

| | R

| | D

| | R

| rowspan=2 | R

| colspan=9 align=right | Majority →

| | R

| | R

| colspan=2 |

| | R

|- valign=top

! Key

{| class=wikitable

| align=center width=35px | D

| Democratic

| align=center width=35px | R

| Republican

Race summary

Special elections during the 66th Congress

In these special elections, the winner was seated during 1920 or before March 4, 1921; ordered by election date.

{| class=wikitable

|- valign=bottom

! rowspan=2 | State

! colspan=3 | Incumbent

! rowspan=2 | Results

! rowspan=2 | Candidates

! Senator

! Party

! Electoral history

! Alabama (Class 2)

| B. B. Comer

| | Democratic

| 1920

| | Interim appointee retired. New senator elected November 2, 1920. Democratic hold.

| nowrap |

! Virginia (Class 2)

| Carter Glass

| | Democratic

| 1920

| Interim appointee elected November 2, 1920.

| nowrap |

Elections leading to the 67th Congress

In these general elections, the winners were elected for the term beginning March 4, 1921; ordered by state.

All of the elections involved the Class 3 seats.

{| class=wikitable

|- valign=bottom

! rowspan=2 | State

! colspan=3 | Incumbent

! rowspan=2 | Results

! rowspan=2 | Candidates

! Senator

! Party

! Electoral history

! Alabama

| Oscar Underwood

| | Democratic

| 1914

| Incumbent re-elected.

| nowrap |

! Arizona

| Marcus A. Smith

| | Democratic

| 1912 1914

| | Incumbent lost re-election. Republican gain.

| nowrap |

! Arkansas

| William F. Kirby

| | Democratic

| 1916

| | Incumbent lost renomination. Democratic hold.

| nowrap |

! California

| James D. Phelan

| | Democratic

| 1914

| | Incumbent lost re-election. Republican gain.

| nowrap |

! Colorado

| Charles S. Thomas

| | Democratic

| 1913 1914

| | Incumbent lost re-election as a Nationalist. Republican gain.

| nowrap |

! Connecticut

| Frank B. Brandegee

| | Republican

| 1905 1909 1914

| Incumbent re-elected.

| nowrap |

! Florida

| Duncan U. Fletcher

| | Democratic

| 1909 1909 1914

| Incumbent re-elected.

| nowrap |

! Georgia

| Hoke Smith

| | Democratic

| 1911 1914

| | Incumbent lost renomination. Democratic hold.

| nowrap |

! Idaho

| John F. Nugent

| | Democratic

| 1918 1918

| | Incumbent lost re-election. Republican gain. Incumbent resigned January 14, 1921 to give successor preferential seniority. Winner appointed January 15, 1921.

| nowrap |

! Illinois

| Lawrence Y. Sherman

| | Republican

| 1913 1914

| | Incumbent retired. Republican hold.

| nowrap |

! Indiana

| James E. Watson

| | Republican

| 1916

| Incumbent re-elected.

| nowrap |

! Iowa

| Albert B. Cummins

| | Republican

| 1908 1914

| Incumbent re-elected.

| nowrap |

! Kansas

| Charles Curtis

| | Republican

| 1907 1907 1913 1914

| Incumbent re-elected.

| nowrap |

! Kentucky

| J. C. W. Beckham

| | Democratic

| 1914

| | Incumbent lost re-election. Republican gain.

| nowrap |

! Louisiana

| Edward J. Gay

| | Democratic

| 1918

| | Incumbent retired. Democratic hold.

| nowrap |

! Maryland

| John W. Smith

| | Democratic

| 1908 1908 1914

| | Incumbent lost re-election. Republican gain.

| nowrap |

! Missouri

| Selden P. Spencer

| | Republican

| 1918

| Incumbent re-elected.

| nowrap |

! Nevada

| Charles Henderson

| | Democratic

| 1918 1918

| | Incumbent lost re-election. Republican gain.

| nowrap |

! New Hampshire

| George H. Moses

| | Republican

| 1918

| Incumbent re-elected.

| nowrap |

! New York

| James W. Wadsworth Jr.

| | Republican

| 1914

| Incumbent re-elected.

| nowrap |

! North Carolina

| Lee S. Overman

| | Democratic

| 1903 1909 1914

| Incumbent re-elected.

| nowrap |

! North Dakota

| Asle Gronna

| | Republican

| 1911 1914

| | Incumbent lost renomination. Republican hold.

| nowrap |

! Ohio

| Warren G. Harding

| | Republican

| 1914

| | Incumbent retired to run for U.S. President. Republican hold. Incumbent resigned January 13, 1921, having won the Presidency. Winner appointed January 14, 1921.

| nowrap |

! Oklahoma

| Thomas Gore

| | Democratic

| 1907 1909 1914

| | Incumbent lost renomination. Republican gain.

| nowrap |

! Oregon

| George E. Chamberlain

| | Democratic

| 1909 1914

| | Incumbent lost re-election. Republican gain.

| nowrap |

! Pennsylvania

| Boies Penrose

| | Republican

| 1897 1903 1909 1914

| Incumbent re-elected.

| nowrap |

! South Carolina

| Ellison D. Smith

| | Democratic

| 1909 1914

| Incumbent re-elected.

| nowrap |

! South Dakota

| Edwin S. Johnson

| | Democratic

| 1914

| | Incumbent retired. Republican gain.

| nowrap |

! Utah

| Reed Smoot

| | Republican

| 1903 1909 1914

| Incumbent re-elected.

| nowrap |

! Vermont

| William P. Dillingham

| | Republican

| 1900 1902 1908 1914

| Incumbent re-elected.

| nowrap |

! Washington

| Wesley L. Jones

| | Republican

| 1909 1914

| Incumbent re-elected.

| nowrap |

! Wisconsin

| Irvine Lenroot

| | Republican

| 1918

| Incumbent re-elected.

| nowrap |

Closest races

Nine races had a margin of victory under 10%:

{| class="wikitable sortable"

! State

! Party of winner

! Margin

! Kentucky