Sen. Tim Johnson (D-S.D.) announced Tuesday afternoon that he will not run for Senate in 2014, and has no plans to seek future political office.
Johnson's departure from the Senate opens up the Senate Banking Committee chairmanship. Johnson, who will exit at the end of his third term, is the fifth Senate Democrat to retire this election cycle.
His decision gives an opportunity to Republicans to pick up a key seat that could help them win a Senate majority.
"South Dakota voters rejected the progressive agenda by nearly 20 points in 2012 and it's a prime pick up opportunity for Republicans regardless of whose name ends up on the ballot after what's shaping up to be a contentious Democratic primary," said National Republican Senatorial Committee Chairman Jerry Moran (R-Kansas) in a statement following Johnson's announcement.
But Democrats pushed back on the idea that Johnson's retirement has delivered the seat to Republicans. Democratic Senatorial Campaign Committee Chairman Michael Bennet (D-Colo.) said in a statement that the timing of Johnson's announcement would give Democrats ample time to recruit a strong contender.
"I appreciate that Senator Johnson has made this decision so early in the cycle, giving Democrats the opportunity to build a winning ticket next year. The DSCC will devote all of the resources necessary to win this seat next year, and I am confident that we can elect a new Democratic senator to continue Senator Johnson’s tradition of service to South Dakotans," he said.
Republicans already have a top recruit in former Gov. Mike Rounds, though he is likely to face a primary challenger from the right.
The Senate Conservatives Fund, the conservative PAC that backed grassroots candidates in Republican primaries in 2012, is looking for just that challenger.
"We already know that we won't be able to support Mike Rounds because his record is too liberal. As Governor, Mike Rounds raised taxes, increased the state's bureaucracy, supported President Obama's stimulus program, and backed bailouts for Wall Street banks," said SCF Executive Director Matt Hoskins in a release.
Rep. Kristi Noem (R) is also looking at a bid, but Hoskins was lukewarm when asked whether SCF would back her.
"At this point, we don't know if she's someone we can support, but we certainly don't object to her running," he told The Hill.
Other lesser-known Republicans could enter the race. State Sen. Larry Rhoden told The Hill he has been encouraged to run by many of his former colleagues in the statehouse, and he is currently looking into it.
"We are in the process of considering options and doing our due diligence" on a potential run, he told The Hill.
Former Lt. Gov. Steve Kirby (R) is also rumored to be considering a run. He did not respond to a request for comment.
Democrats are looking at a potential primary between former Rep. Stephanie Herseth Sandlin and U.S. Attorney Brendan Johnson, son of Sen. Johnson. Both would enter the race with strong name recognition.
But the younger Johnson would likely have his father's war chest, more than $1.2 million at the end of last year, at his disposal, and he'd be free of the legislative baggage Herseth Sandlin earned during her time in the House.
On Tuesday Johnson said he would likely not be heavily involved in the race to replace him, and said that he hadn't had an extended conversation with his son about his potential bid.
“It is no great secret that I’m not running again but I’ve discussed that with he and a lot of other people. But [I have not] discussed in detail what comes next, whether it is Stephanie or Brendan or whoever," he said.
But the more than $1.2 million the elder Johnson currently has in his campaign coffers could provide his son with a solid base on which to build his organization, if Sen. Johnson decided to contribute to his campaign.
The younger Johnson said he has spoken to his father about a potential Senate run "only in very general terms."
"We haven't sat down and made any plans. Through the years I've watched him and I have some idea of the sacrifices that being involved in politics at that level would entail," he said.
But he declined to discuss his future plans, saying only that he's currently focused on his job as U.S. Attorney.
However, Herseth Sandlin would avoid the charges of nepotism that are likely to arise against Johnson, and she fared better than Johnson against both Noem and Rounds in a recent poll. Multiple sources confirmed that the DSCC has reached out to Herseth Sandlin to discuss her potential bid.
But some South Dakota Democrats are pressuring Sandlin to enter the gubernatorial race, hoping to avoid a primary and front strong candidates in multiple statewide races.
“There's a lot of pressure from Democrats in South Dakota for Stephanie to run for governor. That's the golden ring for Democrats in the state. We have gone the longest out of any state under one party rule,” one South Dakota Democratic operative said.
If Herseth Sandlin did run for governor, the advantage for Democrats would be twofold: They’d avoid a potentially bruising Senate primary, and have strong contenders in both the Senate and gubernatorial races.
And running for Senate, Herseth Sandlin could face charges that she's a part of the Washington establishment, having joined a D.C. lobbying firm after her defeat from the House and lived in Washington. She recently moved back to South Dakota, and has been appearing at events around the state.
A former aide to Herseth Sandlin, however, predicted she would be unlikely to jump into the gubernatorial race.
“After serving in the House, I think she is more comfortable with federal office,” the aide said.
--This piece was updated at 6:18 p.m. to reflect comment from Brendan Johnson and details on Herseth Sandlin.