One candidate publicized photos of himself greeting Donald Trump at Mar-a-Lago. Another is offering up a chance to win an Ivanka Trump purse in exchange for sharing an email address with the campaign. A third can't stop tweeting about making America great again.

In the South Carolina race to replace former Rep. Mick Mulvaney, Republican congressional candidates can't do enough to publicly tout their support for President Donald Trump.

But behind the tweets and the giveaways, the race is shaping up as a critical test of whether anti-establishment, populist outsiders can replicate the president's out-of-nowhere win — or if more traditional, credentialed conservative candidates can prevail in the Trump era.

"This is going to tell you where the Republican primary voter is, after all of the carnage that's gone on in the news, the attacks on Donald Trump," said Katon Dawson, a former chairman of the South Carolina Republican Party.

"It's going to show what kind of political juice his message still has, whether somebody is going to get out front and say, 'I want to go help Donald Trump,'" Dawson said. "Do you want somebody who wants to go help Donald Trump or somebody who wants to go help Lindsey Graham and Tim Scott?"

The primary for the special election to replace Mulvaney, now serving as Trump's budget chief, will take place May 2 in the conservative district that includes Rock Hill, just across the state line from Charlotte, N.C. The winner of the primary — or possible runoff — will be the heavy favorite to win the general election in June.

The deadline to file is Monday, and so far at least seven Republicans say they are in the running.

Perhaps none of them has leaned harder into the Trumpian outsider message than Tom Mullikin, a longer-shot lawyer and commander of the South Carolina State Guard who has a record of donating to both Republicans and Democrats — just like Trump, his allies would say.

Last month, he tweeted several pictures of a trip that he and his wife took to Mar-a-Lago — Trump's "winter White House" — where they encountered the president, who was hosting Japanese Prime Minister Shinzo Abe. They spoke — albeit "briefly, briefly" — about the race, Mullikin said, adding that Trump's win inspired him to take a closer look at running.

"There's a strong outsider sentiment. I've been almost surprised at the level, as we've moved around the district over the last few weeks, exactly how strong," he said. "It's palpable."

Sheri Few, an anti-Common Core activist, has also cited Trump and signaled a hard-line immigration stance, in her bid to "make America America again" and stop the "politically correct war on our Judeo-Christian values."

But for all the talk about the outsider mood sweeping the electorate, the three candidates generally considered to be early front-runners have substantial political experience even as they emphasize their support for Trump's nontraditional administration. A similar dynamic was on display earlier this year in a special primary contest in Kansas to fill the seat of new CIA Director Mike Pompeo. There, Alan Cobb, a former top Trump campaign adviser, ultimately lost to state Treasurer Ron Estes.

In the race for South Carolina's 5th Congressional District seat, Tommy Pope, whose campaign is hawking the Ivanka Trump bag, is the speaker pro tempore in the South Carolina House of Representatives and a high-profile former prosecutor — and in the little public polling that is available, he has the early edge.

Ralph Norman, whose Twitter feed is full of tweets and retweets about "making America great again," recently resigned from his Statehouse seat. Chad Connelly is a former chairman of the South Carolina Republican Party who led faith outreach for the Republican National Committee during the 2016 campaign. His team is making the case that he played a key role in facilitating historic evangelical turnout for Trump.

Chip Felkel, a longtime South Carolina Republican strategist, said that typically in a special election, name ID would matter more than whoever most loudly promised to push an outsider approach. Whether that holds true this time will offer insight into whether anyone other than Trump has similar appeal.

"In a state that voted overwhelmingly for Trump, and certainly in the primary was good Trump territory, this will be a good test of whether or not his brand of politics — whatever that exactly is — has legs," Felkel said.

In an interview, Pope acknowledged that voters are in an anti-establishment mindset. But he stressed that wanting to change Washington and having political experience aren't mutually exclusive.

"They are wanting a change, but I think it's a change based on a lack of action, a lack of appropriate action," said Pope, who was elected to the state Legislature in 2010. "In the short time I've been there, I've gotten things done."

Asked Dawson's question — does he want to go to Washington to help Trump or more traditional Republicans like Graham, who has at times been a harsh Trump critic, infuriating the grass roots — Pope replied carefully: "I want to go to Washington to help the United States of America. And so if Donald Trump is helping the United States, I'm supportive. If Lindsey Graham is helping keep us strong, I'm supportive."