“Halfway through my speech, I was thinking, I feel like a gladiator just waiting for the tiger to eat me,” Brian Schweitzer said. (Matt Brown/AP)

PARK CITY, Utah — For a Democrat toying with waging a presidential primary challenge against Hillary Rodham Clinton from the populist left, the exclusive confab of chief executives and Republican donors hosted by Mitt Romney is a most unlikely place to campaign.

But that’s precisely what Brian Schweitzer did this week.

The former Montana governor, MSNBC contributor and 2016 hopeful delivered a stem-winder of a speech to some 300 Republican elites assembled here in a theater-in-the-round setting at a luxury mountaintop resort.

Schweitzer’s remarks Friday afternoon were all over the map — from life lessons he learned as a boy leading his steer at 4-H club showings to his disagreements with the Affordable Care Act and the war in Iraq to sharp criticism of President Obama’s energy policy. And he said the one elected official with whom he agrees on some issues is Sen. Rand Paul (R-Ky.).

During a question-and-answer session, Republican strategist Ana Navarro asked Schweitzer whether he was more relatable to average voters than Clinton is. The rancher-politician said he is, but quickly segued to a diagnosis of Romney and Obama’s likability in the 2012 election.

“I don’t know why you lost the election, Mitt, but I know this: I was watching you on TV and I didn’t see the Mitt Romney that I knew,” Schweitzer said. “You are a fun guy and you’re easy-going and Obama is not. I’ve been in the room with him a little, too. He’s stiff as a board and you’ve got it going on.”

Romney’s got it going on — not exactly a winning slogan for a politician hoping to persuade the Democratic masses.

Schweitzer, never one to shy away from the spotlight, has been auditioning lately for a long-shot presidential bid. Over the past month, he has sat for lengthy interviews with the Wall Street Journal and Time magazine and has been one of the few Democrats publicly criticizing Clinton, leading to speculation that he might try to mobilize the party’s progressive base against her.

Schweitzer said he came to this weekend’s Park City “ideas summit” at the invitation of Romney, a former Massachusetts governor. As governors, Schweitzer and Romney, along with former Missouri governor Matt Blunt (R), traveled together to Iraq and Afghanistan to visit with National Guard troops from their states.

Introducing Schweitzer to donors here, Romney called him “my friend,” adding, “We really enjoyed each other’s time” on the overseas trip.

Romney recalled once telling Schweitzer of his idea to ease congestion of the nation’s most crowded highways: Creating commuter vehicles that are only one-person wide and opening more highway lanes by dividing some in half.

“He looked at me and he said, ‘Mitt, I’d keep that idea to myself,’” Romney said, laughing.

In his remarks, Schweitzer said, “I wasn’t a supporter of the Affordable Care Act.” He criticized Obama’s signature health-care law for catering too much to the insurance and pharmaceutical industries.

Schweitzer made clear that, if he runs in 2016, he would go after Clinton for her Senate vote to authorize military action in Iraq — a vote Clinton writes in her new book, “Hard Choices,” that she got wrong.

“I wouldn’t have voted for that damn war in Iraq and I wouldn’t vote for the next one, I’ll tell you that,” Schweitzer said. “I know too much about the Middle East to put another dime or another son in that war or any of those places.”

Schweitzer also was critical of Obama’s approach to energy. When a donor asked what he thought of the administration’s energy policy, Schweitzer quipped, “There is not an energy policy.” He said he believed human activity was contributing to climate change and, believing his remark would be controversial with his crowd, said, “Go ahead, throw something at me.”

Nobody threw anything. In fact, moments later, Schweitzer appealed directly to one of the biggest GOP donors in the room, billionaire energy investor Harold Hamm.

“Harold, when you’re done getting all the easy oil out of the bottom, what do you need to increase oil production?” Schweitzer asked.

“CO2!” Hamm replied.

Navarro tried to provoke Schweitzer to go after Clinton, who stumbled at the launch of her book tour last week when she said she and her husband left the White House in 2001 “dead broke” and “struggled” to pay the mortgages on their two houses.

“How relatable do you think Hillary Clinton is,” Navarro asked, “and what is your definition of ‘flat broke’?”

“Well, I don’t see any of your friends who are flat broke here, Mitt,” Schweitzer said. “I’ve been flat broke, and I’m not going to defend what she said. She completely misspoke.”

As soon as his speech finished, Schweitzer made a beeline to the press work area to ask reporters how they thought he performed.

Then the Montanan, who came to Park City with no staff and sported jeans and black cowboy boots (he noted they had been dirtied by cow droppings), mingled with the GOP elite at a cocktail reception and private dinner.

Early the next morning, Schweitzer called a Washington Post reporter to say, “Halfway through my speech, I was thinking, I feel like a gladiator just waiting for the tiger to eat me.”

But, as the man who thinks he could become the Democratic Party’s great populist hope observed, “They didn’t throw me out of there!”