Johnson is expected to announce his decision not to seek re-election Tuesday at the University of South Dakota, the Washington publication said. Johnson suffered a stroke in 2006.
His retirement would give Republicans a key opportunity to pick up a seat as they work to regain control of the Senate, The Hill said. GOP presidential candidate Mitt Romney carried South Dakota with 57 percent of the vote in the 2012 election.
Aaron Carter is still in love with Hilary Duff
NBC reportedly holds celebs hostage to Jimmy Fallon's show