Utah Rep. Jason ChaffetzJason ChaffetzTrump, GOP at new crossroads on deficit Chaffetz: Spending vote means GOP 'lost every single bit of credibility' on debt Let’s not fail in our second chance to protect Bears Ears MORE (R) endorsed former Massachusetts Gov. Mitt Romney (R) on Tuesday for president over his onetime boss, former Utah Gov. Jon Huntsman (R). 

Chaffetz, the conservative congressman who's considering a Senate run, picked Romney over Huntsman, both contestants in what's been informally described as the "Mormon Primary." All three men practice the Mormon religion.

"I want to beat Barack ObamaBarack Hussein ObamaOvernight Energy: Dems ask Pruitt to justify first-class travel | Obama EPA chief says reg rollback won't stand | Ex-adviser expects Trump to eventually rejoin Paris accord Overnight Regulation: Trump to take steps to ban bump stocks | Trump eases rules on insurance sold outside of ObamaCare | FCC to officially rescind net neutrality Thursday | Obama EPA chief: Reg rollback won't stand Ex-US ambassador: Mueller is the one who is tough on Russia MORE. Mitt Romney's in the best position to do that," Chaffetz said in a phone interview. "Jon Huntsman's been very good to me. He'll be very formidable now and in the future. He's a good man, but I think Mitt Romney is uniquely situated to beat Barack Obama."

Chaffetz had served as Huntsman's chief of staff before departing to run an ultimately successful primary race to run for the House. While most of Utah's GOP establishment has backed Romney, there had been some thought that Chaffetz might bolt for Huntsman because of their close relationship. 

The three-term congressman explained, though, that he had made prior commitments to supporting Romney before it had even seemed like Huntsman might enter the race. 

"I thought he was maybe a potential candidate in 2016," said Chaffetz, who explained his endorsement to Huntsman in a conversation the congressman described as "a little awkward."

Huntsman had previously declined to take sides in a potential primary next year between Chaffetz and Utah GOP Sen. Orrin HatchOrrin Grant HatchOvernight Finance: NAFTA defenders dig in | Tech pushes Treasury to fight EU on taxes | AT&T faces setback in merger trial | Dems make new case against Trump tax law | Trump fuels fight over gas tax What sort of senator will Mitt Romney be? Not a backbencher, even day one Lawmaker interest in NAFTA intensifies amid Trump moves MORE.

Romney's potential comes down to his experience and finely tuned political organization, explained the congressman. 

"He's also got an organization that's big enough and broad enough to take on President Obama," Chaffetz said. "Mitt Romney's about as well-vetted as anybody out there."

And he had a warning for some of the would-be candidates: "If you're not in the race at this point, it's pretty difficult to build the kind of broad organization you need to win at the national level."

Chaffetz also said that he wouldn't expect Romney to pick sides in a possible matchup against Hatch, since both had expressed their support for the former Massachusetts governor.