In fact, for much of the 19th century it was not uncommon for Supreme Court seats to be unoccupied for months at a time – or, in a few cases, years. But there were only two extended vacancies in the 20th century: the 391 days from the resignation of Abe Fortas in May 1969 to Harry Blackmun’s swearing-in in June 1970, and the 237 days from Lewis Powell’s retirement in June 1987 to Anthony Kennedy’s swearing-in in February 1988. The average duration of the 15 Supreme Court vacancies since 1970 has been just over 55 days – partly because it’s become common for departing justices to make their official retirements contingent on the confirmation of a successor.
We looked at every Supreme Court vacancy since the court was established (with six justices) in 1789-90. Usually we counted vacancies as the number of days between one justice’s death, retirement or resignation and his or her successor’s formal swearing-in. For the 11 justices who first joined the court via recess appointments, we used the appointment date as the endpoint.
By far the longest gap – 841 days, or more than two years – came in the mid-1840s. Justice Henry Baldwin died in April 1844, but the mutual antipathy between President John Tyler and the Whig-controlled Senate (the Whigs actually expelled Tyler from their party) made filling the vacancy all but impossible. The Senate declined to act on any of Tyler’s nominations to fill Baldwin’s seat, and it was still open when James Polk took office in May 1845. The Senate rejected Polk’s first nominee, and his second choice declined to accept. Finally, Robert Cooper Grier was confirmed in August 1846.