LAS VEGAS, Nevada -- He made jokes. He angled away from the camera during the photo op. He even kept the entire event to just five minutes, fleeing the scene without taking questions from the press.

But for Mitt Romney, there was no escaping the fact that he had just stood behind a podium in Las Vegas and graciously accepted the endorsement of Donald Trump.

Theories abound as to why Romney's typically-careful campaign would connect itself to a bombastic firebrand like Trump with a highly-publicized joint appearance. Politico's Maggie Haberman pointed out that the endorsement "cuts off free media oxygen for Newt Gingrich" and "diverts attention from the cable-news focus" on Romney's recent "poor" gaffe.

Whatever the reason, it was plainly obvious here that this was not a proud moment for Romney and his team. As BuzzFeed noted earlier, the candidate was visibly uncomfortable. And after the short event, the operation quickly decamped for Reno.

It's easy to see why they didn't want to dwell on this moment. While Romney isn't immune to charges of campaign pandering, he has consistently treated the election with a seriousness not always apparent among some of his Republican rivals. He flatly rejected the birther message Trump was eagerly pushing last spring. He all but hid from press when he met with Trump last fall. And in December, he was second only to Jon Huntsman in rejecting an invitation to appear in a Trump-moderated debate, which was eventually cancelled.

Romney has long treated Trump as a sideshow, and it seemed clear on Thursday that he now saw himself as a reluctant participant.

Trump, on the other hand, was having a ball. He soaked up the attention with an eagerness and vigor that betrayed his status as a reality TV star, wandering around the lobby of the hotel and giving not one, but three separate mini-press conferences. He boasted that Romney had been courting him for months, trashed Ron Paul as "wasting a lot of time," and even managed to get in a plug for Trump International Hotel, where the event was being held.

"You can see why it's number one in Nevada!" he exclaimed.

At least one campaign aide expressed surprise and a hint of exasperation with Trump's antics, acknowledging that they "didn't know" he was going to speak to press before the event.

Meanwhile, among some actual voters looking on, the event was seen as little more than a Vegas spectacle. As secret service completed a sweep of the ballroom, two couples -- a conservative pair of Romney-supporters from Arkansas, and two self-described "New York Democrats" -- chatted about the goings-on.

"We were just getting a cup of coffee and we saw all the people," said one of the Democrats. "I like Trump. I like his show. But I mean..." her voice trailed off.

"He's much more good-looking in person," said the woman from Arkansas, describing Trump. She added, "We're huge Romney supporters, so I guess this is good for him. Well, I don't know. I mean, I don't see how it could be bad."