Rule 22, the Senate's cloture rule, was adopted in 1917.
Notes on verification
Confirmed by Senate's own historical archives, CRS, and multiple independent secondary sources with consistent date (March 8, 1917) and context (Wilson's armed ships filibuster). [tier=gold indep_score=1.0 clusters=4 claim_tier=everyday | kind=empirical eligibility=high]
Sources
- Filibuster, cloture: US Senate rules featured in abortion debate | Politics News | Al Jazeera (seed:politics_and_current_events)
- https://www.senate.gov/about/powers-procedures/filibusters-cloture/senate-adopts-cloture-rule.htm (corroboration)
- https://www.senate.gov/about/powers-procedures/filibusters-cloture.htm (corroboration)
- https://www.congress.gov/crs-product/R41342 (corroboration)
- https://ballotpedia.org/Cloture (corroboration)
- https://archives-democrats-rules.house.gov/Archives/jcoc2n.htm (corroboration)