The man nominated as Democrats' candidate for Senate in South Carolina might have been a "plant," a high-ranking Democrat suggested Thursday.



House Majority Whip James Clyburn (D-S.C.) called for South Carolina to investigate the circumstances that led to Alvin Greene winning the Democratic Senate primary in his state earlier this week.



"There were some real shenanigans going on in the South Carolina primary," Clyburn said during an appearance on the liberal Bill Press radio show. "I don't know if he was a Republican plant; he was someone's plant."

The third-ranking House Democrat said he found it strange that Greene, a relative unknown prior to Tuesday, was able to produce the money to register and run for Senate despite being unemployed.



Greene allegedly tried to pay the registation fee in cash, and Clyburn said he wondered whether an outside party might have funded both the fee and Greene's campaign, in violation of federal campaign finance laws.



Despite having no real campaign or prior political support in the state, Greene won the primary to face Sen. Jim DeMint (R-S.C.) this fall with nearly 59 percent of the vote — almost 100,000 votes.



The South Carolina Democratic Party called on Greene on Wednesday to drop out of the race after The Associated Press reported that the candidate is facing felony charges for having allegedly displayed pornographic images to a college student.



Adding to the pressure on Greene was Clyburn's call for a probe to look at the possibility that an outside party might have funded Greene's campaign beyond legally permissible limits, and without having disclosed the source of those payments. He also called on the U.S. attorney in the state to investigate Greene's alleged felony.



"I would hope the U.S. attorney down there would look at this," Clyburn said about Greene's qualifications for the ballot, also pointing to Greene's having allegedly tried to pay the fee to run for Senate in cash, despite being unemployed.



"I think there's some federal laws being violated in this race, but I think some shenanigans are going on in South Carolina," Clyburn explained. "Somebody gave him that $10,000 and he who took it should be investigated, and he who gave it should be investigated."



Updated 11:42 a.m.

