Maryland Gov. Martin O’Malley, New York Sen. Kirsten Gillibrand and Minnesota Sen. Amy Klobuchar are among the several dozen Democratic lawmakers listed as hosts for an upcoming fundraiser in Washington. All three are viewed as potential contenders for national office.

The April 15 event is the cornerstone of national Democratic efforts to rally financial support for Colbert Busch, who is locked in a competitive race with former Republican Gov. Mark Sanford for an open Charleston-area House seat.

Colbert Busch’s brother, Comedy Central host Stephen Colbert, is scheduled to appear at the event.

As an early presidential primary state, South Carolina typically attracts attention from ambitious out-of-state politicians seeking to win favor with local power brokers. O’Malley and Gillibrand have both dabbed in Palmetto State politics in recent months.

The Maryland governor and former chairman of the Democratic Governors Association spoke at a South Carolina Democratic Party conference in March and talked up state Sen. Vincent Sheheen as a likely challenger to Republican Gov. Nikki Haley.

Gillibrand, meanwhile, sent a fundraising email for Colbert Busch last week trashing Sanford for his romantic escapades as governor.

“This is the same Mark Sanford who, as governor, disappeared from office and used taxpayer money to visit his mistress,” Gillibrand wrote in an April 2 message. “I talked to Elizabeth and told her we are going to do everything we can to make sure she wins … Republican Party bosses know they can’t run on Sanford’s record, so they are going to attack Elizabeth. She needs us to fight back.”

The New Yorker was a prominent booster of female Democrats in the 2012 cycle, helping raise over $1 million for 15 women running for the House and Senate.

Aiding Colbert Busch isn’t just a cause for Democrats with dreams of 1600 Pennsylvania Ave. The invitation for her April 15 event lists Democratic National Committee Chair Debbie Wasserman Schultz, House Minority Whip Steny Hoyer, South Carolina Rep. Jim Clyburn, Minnesota Sen. Al Franken and Illinois Sen. Dick Durbin, the Democratic whip, as hosts, as well as dozens of additional House members.

Democratic polls have shown Colbert Busch running neck and neck with Sanford in the Republican-leaning 1st District, which Republican Tim Scott won with 62 percent of the vote in November before his appointment to the Senate.

The hope among Democrats is that Sanford is so toxic that Colbert Busch may be able to pull off an upset on that conservative turf. A Public Policy Polling survey last month found that 58 percent of voters in the district view Sanford unfavorably.

The general election is on May 7.

It is unclear whether any presidential hopefuls in either party will travel to South Carolina before then to boost their candidate of choice. Up-and-coming Republicans may not be eager to make themselves fodder for late-night television by draping their arms around Sanford. And it might not be helpful to Colbert Busch to have recognizable national figures dropping into the district and reminding voters that she is, after all, a Democrat.

That’s the straightforward line of attack national Republicans have used so far against Colbert Busch, a university administrator who has sought to present herself to voters as a largely nonpartisan figure.

“Elizabeth Colbert Busch and her ultra-liberal policies are bad match for South Carolina’s fiscally-conservative, hard-working families,” National Republican Congressional Committee communications director Andrea Bozek said in a press release Monday morning.

The April 15 event is one of two big-ticket fundraisers national Democrats are holding for Colbert Busch this month; the other is a New York City event on April 23.

The invitation for the April 15 fundraiser, which a source shared with POLITICO, asks for donations starting at $500 and going up to $10,000 apiece for event chairs.

Those funds will go to a joint fundraising committee set up by Colbert Busch and the South Carolina Democratic Party.