What would it take in the Senate for a conviction and removal of a president—historical examples and current partisan arithmetic?
Executive summary
A president can be removed only if the House impeaches and the Senate convicts by a two‑thirds vote of senators present—normally 67 of 100 if all are present—after which removal is automatic and a separate simple‑majority vote may bar future officeholding [1] [2] [3]. Historical trials show that reaching that supermajority is rare: three presidents have been impeached and none convicted, while the only federal officials actually removed by the Senate have been judges [4] [5].
1. The constitutional math: what the Senate must vote to do
The Constitution gives the Senate sole power to try impeachments and requires the “concurrence of two‑thirds of the Members present” to convict, a procedural threshold that in a 100‑seat Senate normally equates to 67 guilty votes if every senator participates [1] [2] [6]. Upon conviction removal from office is automatic, according to Senate practice dating back to at least the 1936 Ritter trial, while disqualification from future office is treated as a separate determination and—by historical practice—can be imposed by a simple majority [3] [7].
2. What history teaches: narrow margins and rare convictions
Impeachment trials of presidents have repeatedly demonstrated the difficulty of mustering two‑thirds: Andrew Johnson survived by a single vote on multiple articles in 1868, demonstrating both the razor‑thin margins possible and the capacity for party defections to decide outcomes [8] [9]. Bill Clinton was acquitted in 1999, with most Republican‑led prosecutions failing to persuade a supermajority that his misconduct warranted removal [10]. Donald Trump was impeached twice; in his second trial seven Republicans joined Democrats to vote guilty but the tally still fell short of two‑thirds, underscoring how even significant bipartisan defections may be insufficient in today’s polarized Senate [9] [11].
3. The practical obstacles beyond arithmetic
Beyond counting votes, practical legal and political questions complicate removals: senators decide what counts as a “high crime or misdemeanor,” and past trials show senators often weigh constitutional standards, jurisdictional questions (especially for former officials), and political consequences when voting [10] [12]. The Senate’s rules, the chief justice’s role in presidential trials, evidentiary choices, and the decision whether to try a former president can all create friction that makes reaching a two‑thirds threshold harder in practice than in theory [1] [12].
4. Partisan arithmetic in the current era
Because the two‑thirds requirement is fixed, the only realistic route to conviction is substantial bipartisan support; narrow party control is seldom sufficient. Contemporary commentary notes that when one party controls the House or Senate, the other’s numerical strength usually prevents a supermajority except where significant defections occur, and some members explicitly justify acquittals on institutional or jurisdictional grounds rather than solely on facts [13] [10]. Thus, in today’s polarized environment, removal usually demands either a large bipartisan shift in senators’ calculations or an unusually large scandal that convinces enough members across the aisle to break with leadership [14].
5. Competing narratives and political incentives
Senators balance constitutional duty, reelection concerns, and party leadership pressure; historical precedents—from Hamilton’s warning about political motives to the “Republican Recusants” who saved Johnson—show that hidden agendas, regional politics, and personal calculations often determine whether the two‑thirds line is crossed [14] [8]. Sources differ on whether impeachment should be treated as a principally legal or political remedy, and those differences shape both House managers’ strategies and Senate persuaders’ willingness to defect—so any prediction must account for incentives as much as for arithmetic [5] [7].