Who Is Vincent Sheheen?

Democratic presidential candidate Martin O'Malley had all of America asking "Who is Vincent Sheheen?" during Sunday's fourth Democratic debate in Charleston, South Carolina. The short answer is: South Carolina Gov. Nikki Haley's Democratic nemesis.

Sheheen ran against Haley for the governorship of South Carolina in 2010 and again in 2014, losing both times. His name was brought up during the debate by former Maryland Gov. Martin O'Malley to counter Sen. Bernie Sanders' claim he was seeking to reform the Democratic party by relying more on "small, individual campaign contributors" rather than super PACS and big-money donors.

Yes, but, Senator, you never came to campaign for Vincent Sheheen when he was running for governor. In fact, neither of you came to campaign for Vincent Sheheen when he was running for governor.

Sheheen has been a Democratic member of the South Carolina Senate since 2004. He was previously a member of the South Carolina House of Representatives from 2000 to 2004. In 2010, Sheheen lost the race for governor to Haley, pulling in 47.1 percent of the vote compared to her 51.4 percent. Four years later, Sheheen lost again to Haley by a slightly larger margin.

While campaigning during the 2014 gubernatorial race, Sheheen suffered a slip of the tongue that put him and his campaign into the media hot seat and proved not all press is good press. "We are going to escort whore out the door," Sheheen said at a rally in Florence before correcting himself. While it is undeniable he intended to say "her," Sheheen was widely criticized for his seemingly insincere apology.

Curiously enough, Sheheen is one of the key lawmakers behind the 15 minutes of fame that skyrocketed Haley into the Republican Party's inner circle late last year. Sheheen is one of the authors on the bill Haley signed in July to remove the Confederate flag from the State House and Capitol Complex.

A native South Carolinian, Sheheen obtained a law degree from the University of South Carolina and worked as a city prosecutor prior to pursuing a political career. The 44-year-old is married with three children.

It's not surprising O'Malley would name-check Sheheen. On Twitter, the politician has been a vocal advocate for O'Malley, tweeting often about his campaign events and appearances.