Can a member of Congress be arrested while in session?

1. Constitutional text and historical purpose: a shield against political harassment

Article I’s clause on privileges was included to prevent executives or others from using arrests to block legislators from carrying out their duties; the clause explicitly privileges members “except Treason, Felony and Breach of the Peace,” and early framers drew directly on English and colonial practice in doing so ^{[1] [2]}. Encyclopedia and legislative-history summaries note the longstanding origin of the privilege and the Framers’ intent to protect legislative independence ^{[5] [2]}.

2. How the privilege has been interpreted: narrow, not absolute

Scholars and case law show courts narrowly interpret legislative immunity: Speech-or-Debate protections cover legislative acts (debate, voting, committee work) but do not extend to non-legislative conduct such as executing an arrest or seizing property — acts the Court has treated as unprotected and subject to liability ^{[6] [3] [7]}. Justia’s annotated treatment explains that executing an arrest tied to congressional action was held not to be a protected legislative act in Kilbourn v. Thompson and related authorities ^[6].

3. Practical limits: when a member can be arrested despite sessions

Library of Congress analysis and multiple secondary sources repeat the textual carve-outs: members are privileged from arrest “during their Attendance at the Session” and in travel to/from session “except for treason, felony or breach of the peace,” meaning serious crimes or disturbances fall outside the privilege ^{[2] [1]}. Contemporary reporting and verification projects underline that this is not a get-out-of-arrest-free card for routine criminal conduct — criminal arrest remains possible for qualifying offenses ^[4].

4. Speech-or-Debate vs. arrest privilege: two related but distinct protections

Article I contains both the privilege from arrest and the Speech-or-Debate Clause. The former deals with freedom from arrest during certain times; the latter bars questioning for legislative acts. Courts have expanded speech-or-debate protections for aides only when their work is the sort that would be protected if performed by the legislator, but both doctrines have recognized limits — they do not license criminal acts or wholesale extra-constitutional behavior ^{[6] [7] [3]}.

5. Where confusion and misinformation arise

Many summaries and definitions (legal glossaries, websites) phrase the privilege in sweeping terms — “exempted from arrest while attending a session” — which can be read as immunity from criminal arrest; fact-check outlets push back, noting the privilege’s narrow application and that members are not categorically immune from arrest ^{[8] [9] [4]}. The tension between concise dictionary-style descriptions and complex case law fosters public misunderstanding ^{[8] [4]}.

6. Enforcement and real-world precedent: rare and constrained

Historical cases cited in legal commentaries show that when the question turned on whether an act was legislative (and thus protected), courts distinguished between adoption of resolutions (legislative) and the execution of arrests or seizures (non-legislative and potentially liable) — demonstrating that members have been subject to ordinary legal constraints when their conduct steps outside legislative function ^[6]. Contemporary reporting also highlights that commentators and scholars reject the notion of blanket criminal immunity for sitting members ^[4].

7. Bottom line for readers and questioners

The Constitution does grant a narrow privilege protecting attendance and legislative speech to prevent political interference ^{[1] [2]}. Available sources do not support the claim that members of Congress enjoy absolute immunity from arrest while in session; courts and legal commentators limit the protections to legislative acts and exclude treason, felonies, and breaches of the peace, and fact-checkers summarize that members can be arrested under those exceptions ^{[6] [4]}.