Four years ago this week, Mitt Romney surprised attendees at the annual Conservative Political Action Conference by dropping out of the presidential race.

As the American Conservative Union’s gathering of grass-roots activists kicks off again today in Washington, D.C., the former Massachusetts governor finds himself the uneasy frontrunner in a Republican nomination fight that remains hotly contested. He is one of three GOP contenders speaking at the event on Friday, and ACU Chairman Al Cardenas said the state of the race is bringing a welcome buzz to the three-day event.

“For a couple of decades we really haven’t had a very contested, competitive primary heading into CPAC,” Cardenas said in an interview with Roll Call. “For the candidates, it will be the ultimate focus group, because they’ll be on the same day, on the same stage, in front of the same group of people. And we’ll see what kind of reaction they get.”

Romney is coming off big wins in both Florida and Nevada, though he came up short in three states that made their choices Tuesday. The conservative alternative to Sen. John McCain (Ariz.) in 2008, Romney is now struggling to coalesce support across the party spectrum and put away the nomination.

“For the governor, CPAC is another opportunity to bring a message about what can unify conservatives in our effort to defeat President [Barack] Obama in November,” Romney adviser Kevin
Madden said.

As for the other two candidates appearing at CPAC, former Sen. Rick Santorum (Pa.) won Colorado, Missouri and Minnesota this week, breathing life into his campaign. Former Speaker Newt Gingrich (Ga.) has struggled to gain traction since winning South Carolina but has promised to take the race to the national convention in August. Neither campaign responded to a request for comment.

Rep. Ron Paul (Texas), a CPAC favorite and the only presidential candidate still running who has not yet won a state, is skipping the event to campaign in Maine. His son, Sen. Rand Paul (R-Ky.), will speak in his place.

The 2008 CPAC opened just two days after Super Tuesday, from which Romney emerged weakened following big wins by McCain and former Arkansas Gov. Mike Huckabee. Twenty-nine states had already voted by that time, while only eight have completed voting so far in 2012. McCain, now a Romney surrogate, did not know in advance that Romney was dropping out.

“The CPAC event in 2008 just happened to be in concert with the governor’s decision to end his campaign, but it also provided a perfect forum to send a message about bringing the party together at that time,” Madden said.

Some 1,200 media credentials were issued for this year’s event and candidates’ speeches will be broadcast live. About 60 percent of CPAC attendees in recent years have been between the ages of 18 and 25, and about two-thirds are male, according to past straw poll responses.

The list of speakers lined up to address the hotel ballroom crowd includes Speaker John Boehner (Ohio), Senate Minority Leader Mitch McConnell (Ky.), House Budget Chairman Paul Ryan (Wis.), Sen. Marco Rubio (Fla.), former Alaska Gov. Sarah Palin and former presidential candidates Rep. Michele Bachmann (Minn.) and Herman Cain.

The CPAC straw poll has not proved to be a reliable predictor of the GOP nominee, but this year it could serve as a test of conservative support with just four candidates vying for the nomination. Romney won the straw poll in 2007 and again in 2008, even though a majority of respondents that year voted after Romney dropped out.

“Some conservatives in attendance may have had a different first choice,” Madden said, “but Governor Romney’s message about stopping wasteful spending and turning our economy around is a message that all conservatives who participated in the primary process can rally around in support of a general election nominee.”

Cardenas said Romney has his “fair share” of support among the 33 members of the ACU board of directors, which includes Grover Norquist and principals from conservative groups such as the Heritage Foundation and the National Rifle Association and is generally representative of the conservative movement. But despite superior organization and overwhelming establishment support, Romney will still have questions to answer when he steps onto the podium at 1 p.m. Friday.

Cardenas said all three candidates have different missions at CPAC. “Newt has got to show that he is still relevant, and Santorum still has to show that he can be prime time,” he said.

“The hurdle Romney needs to overcome is the authenticity issue, because it’s been brought on so successfully by his opponents in the primary,” Cardenas said. “This is a perfect place to deal with it, and he’s got an opportunity to really hit a home run here and make a difference with that impression.”