How the president’s party has fared in every US midterm election since 1946

Only twice in the past 20 midterms has the president’s party gained House seats. Polls suggest 2026 won’t be the third.

On Tuesday, Americans head to the polls for the United States midterm elections, held halfway through a president’s four-year term. Voters will choose all 435 members of the US House of Representatives and 35 of the Senate’s 100 seats. The voting will decide which party controls Congress for the next two years.

Although the president’s name won’t appear on the ballot, the vote is widely seen as a verdict on the presidency, and the president’s party almost always pays the price.

In 18 of the 20 midterms held from 1946 to 2022, voters took House seats away from the party in control of the White House. The average loss was 26 seats. Only Bill Clinton’s Democrats in 1998 and George W Bush’s Republicans in 2002 bucked the trend.

Political scientists call this the “presidential penalty”, or the “midterm penalty”. The president’s party tends to lose seats simply because it holds power as voters use the midterms to put a check on the White House.

The House: 18 losses in 20 midterms

The chart below shows how many House seats the president’s party has won or lost in each midterm since 1946 from Harry S Truman to Joe Biden.

Democratic presidents have suffered the biggest midterm defeats since 1946. On average, their party has lost about 29 House seats in a midterm, compared with about 23 under Republican presidents.

The largest loss came in 2010, two years after Barack Obama became the first African American elected president, when Democrats lost 64 House seats and Republicans took control of the chamber. The Democrats under Truman lost 56 seats in 1946, and under Clinton, they lost 54 in 1994, each time losing control of the House.

The worst Republican defeats came under Dwight D Eisenhower when the party lost 50 seats in 1958 and Gerald Ford when it lost 48 in 1974. Donald Trump’s first midterm in 2018 cost Republicans 42 seats and control of the House.

Big losses often cost the president’s party its majority. In seven of the 20 midterms since 1946 (1946, 1954, 1994, 2006, 2010, 2018 and 2022), the House changed hands.

The Senate: 13 losses in 20 midterms

The president’s party has lost Senate seats in 13 of the 20 midterms since 1946 but lost control of the chamber in only six: 1946, 1954, 1986, 1994, 2006 and 2014.

Unlike the House of Representatives, where every seat is up for election every two years, only about a third of the Senate’s 100 seats are contested in each cycle because senators serve six-year terms and their elections are staggered. That means which states are voting can matter as much as the national mood.

Eisenhower’s Republicans suffered the biggest Senate loss in the period, giving up 13 seats in 1958. Truman’s Democrats lost 12 in 1946, and Obama’s Democrats lost nine in 2014, handing control of the chamber to Republicans.

At times, the two chambers have moved in opposite directions. In 1982, Ronald Reagan’s Republicans lost 26 House seats but gained one in the Senate. In 2018, Trump’s Republicans lost the House but added a Senate seat, and in 2022, Biden’s Democrats lost the House while gaining one seat in the Senate.

These split results show that a backlash against the president does not land evenly across Congress. A party can hold its ground on a favourable Senate map while losing competitive House districts.

What does it mean to lose the House or Senate?

Losing seats and losing control are not the same thing. Lyndon Johnson’s Democrats lost 47 House seats in 1966 but kept their majority. Twenty years later, Reagan’s Republicans lost only four House seats but lost the Senate after an eight-seat setback.

Control of the chambers decides who sets the agenda and passes legislation. A bill must pass both chambers before it reaches the president for his approval or veto, so an opposition majority in either can block the president’s plans.

A House majority can also mean a party is able to launch investigations and impeach a president while a Senate majority can reject the president’s nominees, including federal judges, who serve for life.

This year, Democrats need to gain three seats to win the House and four to win the Senate. A 50-50 split in the Senate would leave Republicans in control because Vice President JD Vance may cast tie-breaking votes.

过去20次中期选举中，总统所在的政党只有两次在众议院赢得席位。民调显示，2026年不会是第三次。

周二，美国民众将前往投票站参加中期选举，此次选举在总统四年任期过半时举行。选民将选出美国众议院全部435名议员和参议院100个席位中的35个。此次投票将决定未来两年国会由哪个党派控制。

虽然总统的名字不会出现在选票上，但这次投票被广泛视为对总统任期的评判，而总统所在的政党几乎总是要付出代价。

从1946年到2022年举行的20次中期选举中，有18次选民将众议院席位从执政党手中夺走。平均每次选举损失26个席位。只有1998年比尔·克林顿领导的民主党和2002年乔治·W·布什领导的共和党逆势而行。

政治学家称之为“总统惩罚”或“中期选举惩罚”。总统所在的政党往往会因为选民利用中期选举对白宫进行制衡而失去席位，这仅仅是因为该党掌握着权力。

众议院：20次中期选举中失利18次

下图显示了自 1946 年哈里·S·杜鲁门到乔·拜登以来，总统所在政党在每次中期选举中赢得或失去的众议院席位数量。

民主党总统在中期选举中遭遇了自 1946 年以来最大的失败。平均而言，民主党在中期选举中失去了约 29 个众议院席位，而共和党总统执政期间平均只失去了约 23 个席位。

最大的败绩发生在2010年，也就是巴拉克·奥巴马成为美国历史上首位当选总统的非裔美国人两年后。当时民主党失去了64个众议院席位，共和党夺回了众议院的控制权。在杜鲁门执政时期，民主党在1946年失去了56个席位；在克林顿执政时期，民主党在1994年失去了54个席位，两次都失去了对众议院的控制权。

共和党历史上最惨重的失败发生在德怀特·D·艾森豪威尔执政时期（1958年）和杰拉尔德·福特执政时期（1974年），当时共和党失去了50个席位和48个席位。唐纳德·特朗普在2018年的首次中期选举中，共和党失去了42个席位和众议院的控制权。

重大失利往往会导致总统所在政党失去多数席位。自1946年以来的20次中期选举中，有7次（1946年、1954年、1994年、2006年、2010年、2018年和2022年）众议院的控制权易手。

参议院：20次中期选举中失利13次

自 1946 年以来，总统所在的政党在 20 次中期选举中失去了 13 个参议院席位，但只失去了 6 次参议院的控制权：1946 年、1954 年、1986 年、1994 年、2006 年和 2014 年。

与众议院每两年改选一次不同，参议院100个席位中，每次选举只有大约三分之一的席位进行改选，因为参议员任期六年，而且选举错开进行。这意味着各州的投票情况与全国民意同样重要。

艾森豪威尔领导的共和党在这一时期遭受了参议院最大的损失，在 1958 年失去了 13 个席位。杜鲁门领导的民主党在 1946 年失去了 12 个席位，奥巴马领导的民主党在 2014 年失去了 9 个席位，将参议院的控制权拱手让给了共和党。

有时，参众两院的走向截然相反。1982年，罗纳德·里根领导的共和党在众议院失去了26个席位，但在参议院赢得了一个席位。2018年，特朗普领导的共和党失去了众议院的控制权，但在参议院增加了一个席位。2022年，拜登领导的民主党失去了众议院的控制权，但在参议院赢得了一个席位。

这些结果的差异表明，对总统的反弹并未在国会各党派间均衡蔓延。一个政党可能在有利的参议院选区保住阵地，却在竞争激烈的众议院选区失去席位。

失去众议院或参议院的控制权意味着什么？

失去席位和失去控制权并非一回事。1966年，林登·约翰逊领导的民主党在众议院失去了47个席位，但仍然保住了多数席位。20年后，里根领导的共和党在众议院只失去了4个席位，但在参议院却失去了8个席位，最终失去了控制权。

控制参众两院决定了谁能制定议程和通过立法。一项法案必须先经参众两院通过，才能提交总统批准或否决，因此，任何一院的反对派多数都可能阻挠总统的计划。

众议院多数席位也意味着该党能够发起调查并弹劾总统，而参议院多数席位则可以否决总统的提名人选，包括终身任职的联邦法官。

今年，民主党需要赢得众议院三个席位，赢得参议院四个席位。如果参议院两党席位持平，共和党将继续掌控参议院，因为副总统万斯可以投下打破僵局的关键一票。