Sen. Mike Rounds announced he is seeking reelection after a period of uncertainty as his wife underwent cancer treatment in recent months.
The first-term Republican from South Dakota made the announcement the day after voting to acquit President Donald Trump of impeachment charges.
He will face a state representative in the Republican primary.
South Dakota Rep. Scyller Borglum is running against Rounds and has tried to position herself as more right-wing than Rounds, who holds a huge cash advantage over Borglum.
