The record is thin, but it’s not on Martha McSally's side.
On Tuesday, the Arizona Republican was appointed to serve alongside Sen.-elect Krysten Sinema, D-Ariz., the candidate who defeated her in last month’s midterm election. To keep her seat, McSally has to win an election in 2020.
It's only the third time since 1913 — when a constitutional amendment mandated the direct election of senators — that the loser of a Senate contest has gone on to win an appointment to serve with the winner, according to information provided by the Senate Historical Office.
In both of the previous instances, involving Sen. Edwin Mechem, R-N.M., and Sen. Howard Metzenbaum, D-Ohio, the appointed senator lost his next bid for the seat.
In neither previous case was the loser immediately appointed to a vacancy.
In 1954, Mechem lost a race to incumbent Democrat Clinton Presba Anderson. Eight years later, just after he had been defeated for re-election as governor, he had himself appointed to the seat of the late Democrat Dennis Chavez. Mechem ended up serving with Anderson for two years, but, like many governors who move into vacated Senate seats, he lost his bid for election in his own right in 1964.
In 1974, Metzenbaum was appointed to serve alongside Sen. Robert Taft Jr., the Republican who had defeated him in an open-seat Senate race in 1970. Later in 1974, Metzenbaum lost the Democratic nomination to astronaut John Glenn. But he came back in 1976 to defeat Taft.
In addition to those gems, the Senate Historical Office compiled a list of 11 times the losing candidate in a race won a subsequent election and served with the person who defeated him. The most recent example is Republican John Ensign, who won a Senate seat in 2000 after losing to Democrat Harry Reid in 1998. The earliest was Massachusetts Democrat David Walsh, who lost a 1926 contest to Republican Frederick Gillett but rebounded to win a special election later that year and served with Gillett for five years.