It is impossible to quantify exactly how either moved the final results, but in a district where an overwhelming majority of voters are Mormon, it clearly helped to drive a record primary turnout, which contributed to Cannon's surprisingly comfortable margin of victory.
"Between the president and Mrs. Bush's endorsement and the church's statement from the pulpit, those were the two biggest factors that helped Cannon in his re-election," said Ron Fox, who helped run Bush's Utah campaign in 2000 and 2004.
"I think the church's desires were to get people to the polls and vote and I think, as a byproduct, it assisted Cannon in his re-election," he said.
The turnout in the 3rd District primary was nearly 20 percent higher than the 2004 primary, where Cannon was also under fire for his immigration stance.
Getting voters to the polls was considered vital to Cannon's chances to keep his seat. With his immigration views front-and-center, those angered over his position were highly motivated to show up. To prevail, the congressman would need strong turnout among his supporters.
"Turnout usually favors an incumbent in these kinds of situations because when you expand the election pool you are including voters who are going to take into consideration other factors beside the immigration issue," said Kelly Patterson, a political science professor at Brigham Young University, which is owned by the church.
Quin Monson, another BYU professor, downplayed the significance of the church letter, which he said contained fairly "standard language." However, it apparently motivated some people.
"A friend called to tell me that she voted specifically because she heard the letter on Sunday," Monson said.
Church spokesman Dale Bills said, to his knowledge, it was the first time church leaders have urged its members to vote in a primary election.
Bills said that church leaders "regularly teach that church members should make their voices heard as individual citizens of their respective nations by exercising their right to vote."
If there is one place where the church's suggestion would matter most, it is Utah's 3rd Congressional District.
According to a BYU exit poll conducted in the 2004 general election, 74 percent of voters in the district were Mormon. One would expect the LDS concentration to be even higher in the Republican primary, Patterson said, since more Mormons identify themselves as Republicans.
The church leaders said that they were lending their voice at the request of Joe Cannon, chairman of the Utah Republican Party and Chris Cannon's brother, and his Democratic counterpart, Wayne Holland.
Joe Cannon's role in the race had come into question earlier in the campaign after a defense of his brother, including slams against Jacob, showed up on a conservative Web site. He also acknowledged working behind the scenes to help his brother's re-election efforts.
Joe Cannon was traveling on business Thursday and did not return messages seeking comment.
Todd Taylor, executive director of the Utah Democratic Party, said Joe Cannon approached Holland and suggested they make the request to the church, and the Democrats were quick to agree.
But Taylor thinks the letter had limited impact. "But every little bit helps. You did see a higher turnout," he said.
A poll by The Salt Lake Tribune taken before Tuesday's election showed the Cannon-Jacob contest was a dogfight, although the survey was taken before Bush's endorsement and before a series of problems in the Jacob camp surfaced, including his claims that Satan was hampering his ability to adequately finance the campaign and his admission he had gambled in the past.
"It's hard to quantify the impact" of the church statement, said Jeff Hartley, executive director of the Utah Republican Party.
"Based on the Utah County turnout, which was higher than anyone expected, I believe the president had a significant impact on Republican voters and I believe that the church reminding people from the pulpit had a significant impact on the Republican voters, and I hope our efforts as a party had a significant impact."
The church sends more than 50,000 missionaries into the field in 165 countries and more than half the 13 million-plus people on its membership rolls live outside the United States.
The worldwide faith headquartered in Salt Lake City has been thrust into the middle of the immigration issue recently.
A Denver Post story earlier this year looked at the seeming paradox of conservative Utah's image as an immigrant-friendly haven. Chris Cannon was prominently quoted in the piece saying, "The Mormon Church has taken a position that is pretty clear. They are a proselytizing church, and they view the people coming to Utah as a great group of people to convert."
And last month church spokesmen found themselves rebutting claims from CNN commentator Lou Dobbs, a leading anti-illegal immigration voice, who said the church was encouraging as many Mexicans as possible to emigrate to Utah.
The church issued a statement saying it had done no such thing, and has not taken a formal position on immigration policy, "recognizing that this complex question is now before Congress and is already being thoroughly aired in the public square."
Tribune reporter Glen Warchol contributed to this report