How often have U.S. Representatives been expelled historically, and what were the reasons?

1. The constitutional blunt instrument and its threshold

The Constitution empowers each chamber to “punish its Members for disorderly Behaviour, and, with the Concurrence of two thirds, expel a Member,” a high bar that makes expulsion an extraordinary remedy rather than routine discipline ^{[1] [4]}. The House and Senate have built complementary but distinct processes—expulsion requires a two‑thirds vote, whereas exclusion, censure and reprimand follow different standards and majorities—creating legal and procedural guardrails around removals ^{[5] [4]}.

2. The full tally: how many and where

Historically, Congress has expelled 21 members in total: 15 from the Senate and six from the House, a figure repeated in legislative histories and reference works summarizing expulsions through recent cases ^{[1] [2]}. Because tens of thousands have served in Congress, historians emphasize that expulsions are infrequent relative to the size and longevity of the institution ^[6].

3. The Civil War spike: politics, secession, and loyalty

A majority—by many tallies 17 of the 21 expulsions—occurred during and immediately before the Civil War, when senators and representatives who supported secession or the Confederacy were removed for aiding insurrection or refusing allegiance to the Union ^{[2] [3]}. That pattern reflects an era when the chamber’s priority was national survival and political loyalty, producing concentrated use of the expulsion power ^[3].

4. Modern grounds: criminal conduct, corruption and “disorderly behaviour”

Outside the Civil War cluster, expulsions have been driven mainly by allegations of criminality, corruption or conduct deemed to bring disrepute on the institution—recent high‑profile cases illustrate that contemporary expulsions center on misconduct rather than political allegiance ^{[2] [7]}. The House has also preferred lesser sanctions—censure and reprimand—when the facts or political calculus do not support removal, and members under threat have often resigned instead of facing an expulsion vote ^{[7] [1]}.

5. Legal limits and constitutional pushback

Judicial doctrine has drawn distinctions between excluding a Member‑elect and expelling a sworn Member, most famously in Powell v. McCormack, where the Supreme Court curtailed congressional exclusion powers and underscored constitutional limits on denying a duly elected representative his seat—an important check on politically motivated removals ^{[8] [5]}. Scholarship and congressional analyses stress tension between preserving institutional integrity and respecting voters’ choices, a recurrent theme in debates over expulsions ^[8].

6. Politics, precedent and the risk of misuse

Historical antecedents show expulsions have sometimes been used for partisan or ideological ends in earlier parliamentary and colonial practice, prompting post‑Revolution restraint and later judicial oversight to prevent expulsion from becoming a tool for silencing dissent ^{[9] [10]}. Contemporary petitions and advocacy campaigns urge expulsions for wide ranges of misconduct—illustrating political pressure from outside groups—but such calls differ from the institutional standards and two‑thirds threshold that govern actual removals ^[11].

7. Bottom line: rare, clustered, and legally constrained

Expulsion remains the gravest congressional sanction, used rarely and often in historical clusters tied to national crisis (the Civil War) or to clear allegations of criminality and corruption; its application is shaped both by the Constitution’s high vote threshold and by legal precedents that limit Congress’s ability to exclude members outside the defined qualifications ^{[2] [1] [8]}.