Others said the McCain endorsement seemed calculated if not quite Oedipal, a continuation of the younger Huntsman's disengagement from the shadow of his family, an effort that began during the race for governor in 2004, when the father began to recede from public view as the son stepped forward.

Huntsman Sr., who is 69, is still running the giant specialty chemical company he founded, the Huntsman Corp., and still very involved in philanthropy, especially the Huntsman Cancer Institute, a research and treatment center at the University of Utah. But he rarely makes news these days, political experts here say, and he declined to be interviewed for this article. A spokesman for Romney, Kevin Madden, also declined to comment.

Gov. Huntsman, who gave an interview over a lunch of spicy pork tacos from a downtown street vendor, said he and his father had disagreed in "polite respect," and that they rarely talked about politics anyway.

But he said that while his support for McCain was heartfelt and personal, Utah's larger, longer-term interest affected his endorsement decision.

The West, he said, is an emerging political force that is rising in economic and demographic clout and expressing a unique view that he thinks both parties will have to respond to. He praised moderate politicians of both parties, especially Gov. Brian Schweitzer in Montana and Gov. Bill Richardson in New Mexico, both Democrats, as leaders who have caught the new Western spirit. Richardson is seeking his party's nomination for president.

McCain, Gov. Huntsman said, also plans to make Utah a regional hub for the campaign — covering eight or nine states in the interior West — something he said had never happened to Utah in a presidential election.

Western money is flowing, too. Of the $20 million raised by the Romney campaign since January, a significant part came from Utah, at least partly through the efforts of the elder Huntsman.

According to the Huntsman Cancer Institute 2006 annual report and public campaign records, the list of givers to Huntsman causes and Romney supporters overlaps extensively. It includes sports stars like the former Utah Jazz great Karl Malone — who, along with his wife, Kay, donated at least $100,000 to the Huntsman Institute; the Malones also gave $5,000 last year to Romney through his Commonwealth Political Action Committee. And the family of J. Willard Marriott Jr., the wealthy hotelier and fellow Mormon, has given substantially to the Huntsman institute and to Romney.

Marriott said in a telephone interview that his involvement with Huntsman causes and his backing of Romney were coincidental.