Republican U.S. Rep. Mark Sanford raised $162,000 in the first three months of 2018 for his re-election, besting all but one of his four challengers in the battle for campaign dollars.

Sanford holds a commanding money lead overall versus his competition in the 1st Congressional District race, with $1.7 million cash on hand, according to the latest filings Sunday with the Federal Election Commission.

While Sanford's numbers show a slight uptick form the previous reporting period, he has so far been relatively quiet on the campaign trail while one of his Republican primary challengers, state Rep. Katie Arrington of Summerville, has already launched a small round of TV ads.

Arrington reported adding some $310,000 to her campaign war chest for the quarter that ended March 31, but $250,000 of that total came from a loan Arrington made to her campaign.

All told, Arrington, who has aligned herself closely with President Donald Trump and criticized Sanford for going against Trump's agenda, raised close to $60,000 and ended the quarter with about $387,000 cash on hand.

"She is investing into the campaign because she really believes in this," said Michael Mule, Arrington's campaign consultant. "She's not doing this for personal fame or selfish reasons. She's doing this to serve."

There were no filings for Dimitri Cherny, a liberal Democrat who has filed as a Republican to challenge Sanford in the GOP primary.

Meanwhile, Democrat Joe Cunningham hauled in $221,000 in contributions, according to numbers supplied by his campaign. That's about 30 percent more than Sanford did from January through March. 

The campaign disclosure reports for Cunningham had not been posted on the FEC website as of Sunday evening.

Cunningham, who has pledged not to accept any money from special interest political action committees, criticized Sanford for accepting $22,000 from PACs during the last quarter.

"While our opponents continue to rely on special interest PACs and personal wealth, our campaign is being fueled by a grassroots army of real people," Cunningham said in a media release.

Democrat Toby Smith, a self-identified protest candidate in the race, has also started hauling in campaign dollars since announcing her run in mid-March. Smith reported close to $7,500 in contributions with about $1,000 coming from the candidate herself.

Smith ended the fundraising quarter with $2,100 cash on hand.

Scott Buchanan, a political science professor at The Citadel, said he was somewhat surprised that a Democrat out-raised Sanford. However, Buchanan said he doesn't think it's enough to flip the district.

"I think that Arrington has a better chance of beating Sanford than any Democrat," Buchanan told The Post and Courier. "There have been a lot of experts who have predicted the demise of Mark Sanford, and Sanford is always the one laughing at the end."

The nonpartisan Cook Political Report lists South Carolina's 1st Congressional District as a "likely Republican" win.

Sanford, the state's former governor from Mount Pleasant, won the congressional seat in 2013 in a special election, returning to Capitol Hill where he served three terms in the 1990s. Sanford has never lost an election.

The Republican and Democratic primaries are June 12.

Reach Caitlin Byrd at 843-937-5590 and follow her on Twitter @MaryCaitlinByrd.

Caitlin Byrd is a political reporter at The Post and Courier and author of the Palmetto Politics newsletter. Before moving to Charleston in 2016, her byline appeared in the Asheville Citizen-Times. To date, Byrd has won 17 awards for her work.