Romney, who took more than 90 percent of the Republican presidential primary vote in Utah, pleaded with the state's delegation early Monday to throw all their support behind McCain as the nominee.
"I know a couple of you in this room, most of them my relatives, who would like to vote for me when the delegates get counted," Romney said, joking about the relatives part. "Don't do that."
Romney - a former candidate who later told reporters he wasn't interested in a Cabinet spot or running for president again - said he wants to make sure it's loud and clear that his supporters back McCain.
But three Utah delegates, led by Utah National Committeewoman Nancy Lord, who has broke with party elders before, say they must stick by the rules and cast ballots for the candidate the voters supported. Lord wrote a letter to the convention secretary warning that the Utah delegation was not unanimous in its support and that bylaws call for a delegate-by-delegate count.
Lord says she's hoping to avoid a public disagreement by calling for the actual roll call of Utah delegates but is unsure Gov. Jon Huntsman Jr., the head of the delegation, will allow her to cast a ballot for Romney. "I don't necessarily want it to go to that," she said of a roll call vote.
One of those pushing that move is Don Guymon, an avowed Ron Paul supporter who said in an interview that he wants to be able to vote for Mitt Romney.
"My intent isn't to showboat, it isn't to grandstand," Guymon said. "My intent is to uphold my promise to vote for Mitt Romney."
Another delegate, Brian Jenkins, may cast his vote for Ron Paul if allowed.
The Utah Republican Party Central Committee changed its rules in August by a 70-12 vote to throw its support behind the "candidate" for president at the convention, a move that in turn will allow the delegates who were bound for Romney by the primary vote to cast their support behind McCain.
McCain's name is the only one expected to be submitted for nomination.
Jeff Hartley, a GOP activist and alternate delegate, says Lord and her colleagues are just seeking attention. "This is a case of sore losers who don't like the fact that a supermajority of the governing body voted against them," Hartley said.
Romney, who won all of Utah's 36 delegate votes, met with the entire group Monday morning and joked that they should not only back McCain, but vote twice for him.
"Let's be unified on this," he said.
Talking to reporters after the breakfast, Romney said "no thanks" to a 2012 run for the presidency. "I do not anticipate doing it again," he said, noting that he also wasn't interested in a Cabinet spot in a McCain administration.
He gave no hints of what he would do now besides stumping for McCain and other Republican candidates. Romney launched a political action committee this summer to raise funds for federal and state candidates.
"I haven't given a lot of thought to what I do after November," he said.