Weiland, who was appointed to the Federal Emergency Management Agency by former President Clinton and was a candidate for the House in 1996 and 2002, told the Argus Leader that he's not worried about the challenge he'll face running for Senate.

“I’m running for things I strongly believe in,” he said. “I really believe there’s a hunger for political leadership in this country that is really willing to stand up, regardless of the political consequences or the big money.”

According to the Leader, Weiland already has the support of his former boss, former Senate Majority Leader Tom Daschle (D). The two spoke prior to Weiland's announcement and, Daschle said, "I encouraged him with great enthusiasm."

Weiland told the paper that he had also spoken with U.S. Attorney Brendan Johnson (D) — son of retiring Sen. Tim JohnsonTimothy (Tim) Peter JohnsonCornell to launch new bipartisan publication led by former Rep. Steve Israel Trump faces tough path to Fannie Mae, Freddie Mac overhaul Several hurt when truck runs into minimum wage protesters in Michigan MORE (D) — before announcing his plans, and Johnson had indicated he was unlikely to enter the race.

“He’s focused on his job. I wouldn’t be here if I didn’t feel that Brendan (wasn’t) going to get into this race," Weiland said.

Lincoln County Democratic Party Chairman Ryan Casey, a Johnson supporter and founder of a campaign to draft him into the Senate race, echoed Weiland's sentiment and called for his fellow Johnson supporters to back Weiland instead.

"I spoke recently with Brendan Johnson, and he informed me that he will continue to focus on his responsibilities as South Dakota's U.S. Attorney. I'm certain that Brendan will not enter the race for the U.S. Senate, and I hereby call on all those who have signed on to our open letter to give Rick Weiland our full support," he said in an email.

Johnson himself told the paper that his "focus remains strictly on being the state's chief federal law enforcement officer," and declined to discuss politics, comments he's made before when asked about the Senate race.

Focus will now shift to Herseth Sandlin, who is still considering a run but said in a statement to the Argus Leader that "anyone and everyone is welcome to join the race."

The former congresswoman looks to be the favorite of Washington Democrats, who have polling that indicates she'd be stronger in a general election match-up against the only announced Republican candidate, former Gov. Mike Rounds.

South Dakotans are still familiar with her, and her centrist voting record would appeal to voters in a state that leans increasingly red. Herseth Sandlin voted against President Obama's healthcare overhaul and is supportive of gun rights, positions that have drawn fire from progressive activists but would make her competitive in a general election.

Those progressives, however, backed Johnson, and now appear to be backing Weiland, setting up a potential primary fight between two wings of the Democratic Party. Herseth Sandlin defeated Weiland once in a primary during her first run for Congress, in 2002, when she took 58 percent of the vote to Weiland's 32 percent.

Republicans, too, could see a primary fight, as conservatives in South Dakota are dissatisfied with Rounds. They haven't yet found a primary challenger, but some are pushing Rep. Kristi Noem (R), who defeated Herseth Sandlin in 2010, to run.