1948 United States Senate elections

The 1948 United States Senate elections were held concurrently with the election of Democratic President Harry S. Truman for a full term. The 32 seats of Class 2 were contested in regular elections, and one special election was held to fill a vacancy. Truman campaigned against an "obstructionist" Congress that had blocked many of his initiatives, and additionally, the U.S. economy recovered from the postwar recession of 1946–1947 by election day.

Thus, Truman was rewarded with a Democratic gain of nine seats in the Senate, enough to give them control of the chamber. This was the first time since 1936 that Democrats posted a net gain of seats in the chamber. This was the last time until 2020 that Democrats flipped the Senate in a presidential election cycle.

Results summary

{| style="width:50em; text-align:center"

|+ ↓

|- style="color:white"

| style="background:; width:56.25%" | 54

| style="background:; width:43.75%" | 42

| Democratic

| Republican

Colored shading indicates party with largest share of that row.

{| class=wikitable style=text-align:center

! colspan=2 rowspan=2 | Parties

! rowspan=2 | Total

|- valign=bottom

! Democratic

! Republican

! Other

! colspan=2 | Last elections (1946) Before these elections

| 45

| | 51

| 0

! 96

! colspan=2 style="background:#ccc" | Not up

| 30

| | 33

| 0

! 63

! colspan=2 style="background:#ccc" | Up

| 15

| | 18

| 0

! 33

! rowspan=2 |

! style="background:#ddd" |

| 14

| | 18

| 0

! 32

! style="background:#ddd" |

| | 1

| 0

| —

! 1

| colspan=100 |

! colspan=2 style="background:#ccc" | Incumbent retired

| 3

| | 5

| —

! 8

! rowspan=3 |

| 3

| | 4

| —

! 7

| colspan=2 | 1 Republican replaced by 1 Democrat

| —

! 1

! 4

! 0

! 8

! colspan=2 style="background:#ccc" | Incumbent ran

| 12

| | 13

| —

! 25

! rowspan=4 |

| | 10

| 5

| —

! 17

| colspan=2 | 8 Republicans replaced by 8 Democrats

| —

! 8

| | 2

| 0

| —

! 2

! | 20

! 5

! 0

! 25

| colspan=99 |

! colspan=2 | Total elected

! | 24

! 9

! 0

! 33

! colspan=2 | Net change

| | 9

| 9

| colspan=99 |

! colspan=2 style="background:#ccc" | Nationwide vote

| | 13,056,944

| 9,764,384

| 269,669

! 23,090,997

!

! Share

| | 56.55%

| 42.29%

| 1.17%

! 100%

! colspan=2 | Result

! | 54

! 42

! 0

! 96

Source: Clerk of the U.S. House of Representatives

Gains, losses, and holds

Retirements

Five Republicans and three Democrats retired instead of seeking re-election.

{| class="wikitable sortable plainrowheaders"

! scope="col" |State

! scope="col" |Senator

! scope="col" |Replaced by

! Kansas

| |

! Louisiana (special)

| |

! Maine

| |

! New Jersey

| |

! New Mexico

| |

! Oklahoma

| |

! South Dakota

| |

! Texas

| |

Defeats

Eight Republicans and two Democrats 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

! Delaware

| |

! Idaho

| |

! Illinois

| |

! Iowa

| |

! Kentucky

| |

! Minnesota

| |

! North Carolina

| |

! Tennessee

| |

! West Virginia

| |

! Wyoming

| |

Post election changes

{| class="wikitable sortable plainrowheaders"

! scope="col" |State

! scope="col" |Senator

! scope="col" |Replaced by

! Connecticut

| |

! New York

| |

! New York

| |

! North Carolina

| |

! Idaho

| |

! Kansas

| |

! Kentucky

| |

! Rhode Island

| |

Change in composition

Before the elections

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

| colspan=2 |  

| | D

| width=10% | D

| | D

| | D

| | D

| | D

| | D

| | D

| | R

| rowspan=2 | R

| colspan=9 align=right | Majority →

| | R

| | R

| colspan=2 |

| | R

Election results

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

| colspan=2 |  

| | D

| width=10% | D

| | D

| | D

| | D

| | D

| | D

| | D

| colspan=9 align=right | Majority →

| rowspan=2 | D

| | R

| | D

| | R

| | R

| colspan=2 |

| | R

|- valign=top

! Key:

{| class=wikitable

| align=center | D

| Democratic

| align=center | R

| Republican

Race summaries

Special elections during the 80th Congress

In these special elections, the winner was seated during 1948 or before January 3, 1949; ordered by election date.

{| class="wikitable sortable"

|- valign=bottom

! rowspan=2 | State

! colspan=3 | Incumbent

! rowspan=2 | Results

! rowspan=2 | Candidates

! Senator

! Party

! Electoral history

! Louisiana (Class 3)

| | Democratic

| 1948

| | Interim appointee retired. Winner elected November 2, 1948. Democratic hold.

| nowrap |

! North Carolina (Class 2)

| | Democratic

| 1946

| | Interim appointee lost nomination. Winner elected November 2, 1948. Democratic hold. Winner also elected to the next full term.

| nowrap |

Elections leading to the next Congress

In these general elections, the winners were elected for the term beginning January 3, 1949; ordered by state.

All of the elections involved the Class 2 seats.

{| class="wikitable sortable"

|- valign=bottom

! rowspan=2 | State

! colspan=3 | Incumbent

! rowspan=2 | Results

! rowspan=2 | Candidates

! Senator

! Party

! Electoral history

! Alabama

| | Democratic

| 1946

| Incumbent re-elected.

| nowrap |

! Arkansas

| | Democratic

| 1942

| Incumbent re-elected.

| nowrap |

! Colorado

| | Democratic

| 1936 1942

| Incumbent re-elected.

| nowrap |

! Delaware

| | Republican

| 1942

| | Incumbent lost re-election. New senator elected. Democratic gain.

| nowrap |

! Georgia

| | Democratic

| 1932 1936 1942

| Incumbent re-elected.

| nowrap |

! Idaho

| | Republican

| 1946

| | Incumbent lost re-election. New senator elected. Democratic gain.

| nowrap |

! Illinois

| | Republican

| 1940 1942

| | Incumbent lost re-election. New senator elected. Democratic gain.

| nowrap |

! Iowa

| | Republican

| 1942

| | Incumbent lost re-election. New senator elected. Democratic gain.

| nowrap |

! Kansas

| | Republican

| 1918 1924 1930 1936 1942

| | Incumbent retired. New senator elected. Republican hold.

| nowrap |

! Kentucky

| | Republican

| 1946

| | Incumbent lost re-election. New senator elected. Democratic gain.

| nowrap |

! Louisiana

| | Democratic

| 1936 1942

| Incumbent re-elected.

| nowrap |

! Maine

| | Republican

| 1930 1936 1942

| | Incumbent retired. New senator elected. Republican hold.

| nowrap |

! Massachusetts

| | Republican

| 1944

| Incumbent re-elected.

| nowrap |

! Michigan

| | Republican

| 1942

| Incumbent re-elected.

| nowrap |

! Minnesota

| | Republican

| 1940 1942 1942

| | Incumbent lost re-election. New senator elected. Democratic–Farmer–Labor gain.

| nowrap |

! Mississippi

| | Democratic

| 1941 1941 1942

| Incumbent re-elected.

| nowrap |

! Montana

| | Democratic

| 1934 1936 1942

| Incumbent re-elected.

| nowrap |

! Nebraska

| | Republican

| 1942

| Incumbent re-elected.

| nowrap |

! New Hampshire

| | Republican

| 1936 1942

| Incumbent re-elected.

| nowrap |

! New Jersey

| | Republican

| 1942

| | Incumbent retired. New senator elected. Republican hold.

| nowrap |

! New Mexico

| | Democratic

| 1933 1934 1936 1942

| | Incumbent retired. New senator elected. Democratic hold.

| nowrap |

! North Carolina

| | Democratic

| 1946

| | Interim appointee lost nomination. New senator elected. Democratic hold. Winner also elected to finish the term, see above.

| nowrap |

! Oklahoma

| | Republican

| 1942

| | Incumbent retired. New senator elected. Democratic gain.

| nowrap |

! Oregon

| | Republican

| 1944 1944

| Incumbent re-elected.

| nowrap |

! Rhode Island

| | Democratic

| 1936 1942

| Incumbent re-elected.

| nowrap |

! South Carolina

| | Democratic

| 1941 1942

| Incumbent re-elected.

| nowrap |

! South Dakota

| | Republican

| 1948

| | Interim appointee retired. New senator elected. Republican hold. Incumbent resigned December 26, 1948 and winner appointed December 31, 1948 to finish the term.

| nowrap |

! Tennessee

| | Democratic

| 1938

| | Incumbent lost re-nomination. New senator elected. Democratic hold.

| nowrap |

! Texas

| | Democratic

| 1941 1942

| | Incumbent retired. New senator elected. Democratic hold.

| nowrap |

! Virginia

| | Democratic

| 1946

| Incumbent re-elected.

| nowrap |

! West Virginia

| | Republican

| 1942

| | Incumbent lost re-election. New senator elected. Democratic gain.

| nowrap |

! Wyoming

| | Republican

| 1942

| | Incumbent lost re-election. New senator elected. Democratic gain.

| nowrap |

Closest races

Six races had a margin of victory under 10%:

{| class="wikitable sortable"

! State

! Party of winner

! Margin

! Idaho

| data-sort-value=-0.5 | Democratic (flip)

| 1.5%

! Michigan

| data-sort-value=-0.5 | Republican

| 2.2%

! Delaware

| data-sort-value=-0.5 | Democratic (flip)

| 2.6%

! New Jersey

| data-sort-value=-0.5 | Republican

| 2.7%

! Kentucky

| data-sort-value=-0.5 | Democratic (flip)

| 3.1%

! Massachusetts

| data-sort-value=-0.5 | Republican

| 6.6%

Wyoming is the tipping point state with a margin of 14.2%.

Alabama

North Carolina (regular)

Broughton was seated December 31, 1948 to finish the current term but died March 6, 1949, just after the new term began. His death lead to another appointment (Democrat Frank Graham) in 1949 and another special election in 1950 of Democrat Willis Smith. Smith also died during the term, leading to yet another appointment (Democrat Alton A. Lennon) and 1954 special election (of Democrat W. Kerr Scott). In all, five senators held the seat during the 1949–1955 term.

Oklahoma

Incumbent Democrat W. Lee O'Daniel decided to retire rather than seek a second full term. Congressman Lyndon Johnson won the highly contested Democratic primary against former governor Coke Stevenson. Johnson went on to win the general election against Republican Jack Porter, but by a closer margin than usual for Texas Democrats.