What is the constitutional basis for impeachment and conviction vote thresholds?
Executive summary
The Constitution gives the House the “sole Power of Impeachment” and the Senate the “sole Power to try all Impeachments,” and it requires the “Concurrence of two thirds of the Members present” in the Senate to convict; with 100 senators present that means 67 votes (or a pro rata number if fewer senators are present) [1] [2]. The Constitution also limits impeachment judgment to removal and possible disqualification; the Senate has treated disqualification as a separate, simple-majority vote even though the Constitution does not specify that threshold [3] [4].
1. Constitutional text and its clear thresholds
The framers wrote impeachment rules into Articles I and II: the House “shall have the sole Power of Impeachment,” the Senate “the sole Power to try all Impeachments,” and no person may be “convicted without the Concurrence of two‑thirds of the Members present” (U.S. Const. Art. I, §3) — language the Senate and its institutional guides still treat as the operative conviction threshold [1] [5].
2. How the two‑thirds rule works in practice
Senate practice interprets the phrase “two‑thirds of the Members present” to mean two‑thirds of those seated for the vote; if all 100 senators are present, conviction requires 67 votes, and smaller quorums lower the numeric threshold proportionally (for example, 97 senators present would require 65 votes) [2]. The Senate’s procedural manuals and Congressional Research Service material state this plainly [2].
3. House impeachment: simple majority, but flexible rules
The Constitution gives the House the sole power to impeach and historically the House adopts its own voting rules for when an article is approved. Practically, impeachment in the House has been accomplished by a simple majority vote of those voting or present under House rules; the Constitution does not spell out a numeric formula beyond vesting the power in that chamber [1] [4].
4. Removal vs. disqualification — a constitutional gap filled by Senate practice
Article II says removal follows impeachment and conviction, and Article I limits judgment “not extend further than to removal from office, and disqualification” [3]. The Constitution is silent about what vote is needed to impose disqualification after conviction. The Senate has historically treated disqualification as a separate judgment that can be imposed by a simple majority, a position grounded in practice and Senate precedent rather than express constitutional text [3] [4].
5. Why the framers set a high Senate bar
The two‑chamber split and a supermajority conviction rule express a structural safeguard: the House accuses; the Senate checks removal. Multiple sources describe the design as part of checks and balances — a high Senate threshold makes removal rare, reserving it for conduct that wins broad consensus [1] [6].
6. Real‑world consequences: numbers matter politically
The numerical implications are concrete. A 57–43 guilty vote in the Senate fell 10 votes short of conviction in the second Trump trial because two‑thirds of 100 is 67 [7] [2]. That illustrates how the constitutional math transforms political disputes into arithmetic barriers to removal.
7. Disputes and jurisdictional arguments the record records
Sources show the Senate itself has sometimes split over whether trials of former officials are even constitutional; those votes can affect outcomes even when a majority favors conviction, because the two‑thirds rule still governs actual removal and the Senate has considered jurisdictional and procedural objections [5] [8]. Different senators have publicly cited concerns about constitutionality as a reason to acquit despite agreeing the conduct was improper [5].
8. Limits of the sources and remaining open questions
Primary sources above establish text, Senate practice on two‑thirds, and the Senate’s approach to disqualification, but they do not resolve some interpretive debates — for example, whether disqualification should constitutionally require two‑thirds rather than a simple majority is contested in scholarship and practice; the Constitution itself is silent and sources note the argument exists but point to the Senate’s historical choice [3]. Available sources do not mention any recent constitutional amendment proposals to change these thresholds (not found in current reporting).
Sources cited: U.S. Senate and Congressional materials on impeachment [1] [2], Constitution Annotated and Justia analyses on judgment and disqualification [5] [3], explanatory summaries and historical reporting including Wikipedia and TIME for context on past votes [4] [8].