A party last had a 60-seat majority in the U.S. Senate in 2009–2010 , when Democrats briefly reached that mark after Arlen Specter switched parties and before Scott Brown took office. More generally, the last filibuster-proof Democratic majority was in 1977–1979 , when they held 62 seats.

Recent example

  • April 2009 to February 2010: Democrats had 60 seats in the Senate for part of that period.
  • That 60-seat stretch was not continuous for the whole Congress; it came in two brief windows in 2009–2010.

Earlier high-water mark

  • 1977–1979: Democrats held 62 seats, which is the last time a party had a filibuster-proof majority in the Senate.
  • The Senate filibuster threshold has been 60 votes since 1975, so that 62-seat majority easily cleared it.

Historical note

  • Since then, 60-seat Senate majorities have been rare, and modern Senate control has mostly been much narrower.

TL;DR

  • Last 60-seat majority: Democrats, 2009–2010.
  • Last filibuster-proof majority: Democrats, 1977–1979.