A fifth Republican senator has announced he will not seek re-election.
The latest is Roy Blunt, 71, from Missouri who announced Monday on Twitter that he will not run in 2022.
"After 14 general election victories -- three to county office, seven to the United States House of Representatives, and four statewide elections -- I won't be a candidate for reelection to the United States Senate next year," Blunt said in a video he posted on Twitter.
Senators Richard Burr (R-N.C.), Pat Toomey (R-Pa.), Rob Portman (R-Ohio) and Richard Shelby (R-Ala.) have all announced that they will retire at the end of their current terms.
No Senate Democrats have announced retirement plans so far, although California will hold an election in 2022 to fill the seat vacated by Kamala Harris before she became vice president. The seat is currently held by Alex Padilla, who was appointed by California's governor.