An odd thing has happened along the campaign trail over the past 24 hours: House Republican freshmen have taken starring roles in their party’s presidential primary.

Rep. Tim Scott (R-S.C.), center, is among the House GOP freshmen taking an active role in the presidential contest. (AP Photo/Evan Vucci)

To wit:

— Rep. Michael Grimm (N.Y.), a freshman who has endorsed Mitt Romney, on Thursday called on Romney’s rival candidates to halt their attacks on the former Massachusetts governor’s record at the helm of Bain Capital. Grimm has been a regular presence on TV and also hit the campaign trail for Romney in New Hampshire.

— Freshman Reps. Cory Gardner (Colo.), Adam Kinzinger (Ill.) and Ben Quayle (Ariz.) did the same in a letter Friday morning to all six GOP primary contenders. “Class warfare is a tactic that President Obama has used to divide America and campaign against Republicans,” wrote the three freshmen, who so far haven’t endorsed an candidate. “Republican candidates for president should not be stooping to the same level.”

— On Friday night, two South Carolina freshmen, Reps. Trey Gowdy and Jeff Duncan, are moderating a presidential forum sponsored by the Greenville and Spartanburg County Republican Parties. Former House speaker Newt Gingrich, former senator Rick Santorum and former Utah governor Jon Huntsman are scheduled to attend.

— And at noon Saturday, Rep. Tim Scott (S.C.), one of two freshmen tapped to serve as liaisons to House GOP leadership, will co-host a presidential town hall for undecided voters with Arkansas governor Mike Huckabee (R). Romney and Santorum are among the candidates expected to attend.

To be sure, influential voices within the campaigns have weighed in on the race (most recently, Rick Perry’s former backer, Barry Wynn, who announced on Thursday that he is now supporting Romney). But it’s noteworthy that Republican congressional leaders have mostly stayed away from the primary fray.

Senate Minority Leader Mitch McConnell (Ky.), House Speaker John Boehner (Ohio), House Majority Leader Eric Cantor (Va.) and Republican National Committee Chairman Reince Priebus have not commented on the attacks on Romney's management at the private equity firm.

Their hesitance could be a sign that those leaders, aware of how unpopular Congress is in the public’s view – may not want to risk having a candidate be seen by voters as beholden to the party establishment.

Or GOP leaders may simply be keeping to their pledge not to get involved in their party’s nominating fight. Boehner has said that he has no plans to endorse in the race and told conservative commentator Laura Ingraham in October that “it’s important to allow those who show up in the Republican primary to choose the candidate of their choice.”

It could also be that the freshmen view themselves as their party's referees -- calling the shots on what they view as in or out of bounds — a role they have sought to play over much of the last year in battles over spending and the debt ceiling.

Whatever the reason, it is a marked departure from precedent, such as in the 2008 race, when Democratic party elders such as Rep. James Clyburn (S.C.), the late Sen. Ted Kennedy (Mass.) and governors from various states politely but firmly chided former President Bill Clinton some of his remarks about then-Sen. Barack Obama (Ill.). Clinton, of course, was stumping for his wife, now Secretary of State Hillary Rodham Clinton, in her battle for the party’s presidential nomination.

Thoughts? The comments section is open for business.

Staff writer Paul Kane contributed to this report.