In a letter to GOP delegates dated Friday, Bush says he strongly supports Cannon for the 3rd Congressional District, a move the president made when Cannon was challenged for the Republican nomination in 2006 as well.

"It is important that Chris wins," Bush writes in a letter paid for by the Republican National Committee. "Now more than ever, we need experienced, strong and principled leaders in Congress. We need him to continue his work in the House of Representatives."

Cannon faces an intraparty challenge by Jason Chaffetz, the former chief of staff to Gov. Jon Huntsman Jr., and by David Leavitt, the former Juab County prosecutor whose brother is Health and Human Services Secretary Mike Leavitt. Mike Leavitt also is a former governor of Utah.

David Leavitt called the letter "standard protocol" and said that Bush, as a matter of policy, endorses every Republican incumbent not under criminal indictment. But Leavitt is not sure whether his brother, Mike Leavitt, can marshal forces behind him now that Bush has endorsed.

"Once the neutrality line has been crossed that logically would free up others," David Leavitt said. "But what that means, I'm not sure. Quite frankly if I'm going to get the Republican nomination, I'm going to get it on my own merits. [I'm] not sure it changes the equation as far as Mike Leavitt [endorsing him] is concerned."

Likewise, Chaffetz says he isn't that shocked by the letter because he expected Bush to lend Cannon his support.

"Mr. Cannon carried his water on immigration and on No Child Left Behind," Chaffetz said, raising two of the more controversial issues with conservative voters. "They tend to protect their own."

Bush endorsed Cannon in 2006 when he faced a GOP opponent for the nomination; the president recorded a voice message phone banked to voters in the 3rd District in that race, but not until Cannon was facing a primary election.

Leavitt says the timing of the letter is interesting because it comes right before Saturday's GOP State Convention, where Cannon needs to get 60 percent of the delegates to avoid a primary.

"What is significant is the timing of it," Leavitt said. "Last cycle he waited until the primary. This cycle he's doing it in the convention."

In his letter, Bush praises Cannon for his work as a senior member of the House Judiciary Committee and for spending countless hours "helping my administration in the fight against global terrorism.

"We depend on Chris and need his continued service," Bush writes.

He also lauded Cannon for helping to keep the Internet tax-free and for the Second Chance Act, both bills Bush signed this year.

If Cannon does end up in a primary battle, he could get a second helping of Bush support when the president visits Utah on May 28 and 29. The president will be dropping in on the state for a pair of fundraisers on those days.

tburr@sltrib.com