PROVO — Former congressional hopeful John Jacob pushed to make illegal immigration the key issue of last week's Republican primary in the 3rd Congressional District, but exit poll results show the issue polarized voters in favor of his opponent, Rep. Chris Cannon.

Cannon won the primary by taking 55.8 percent of the vote to Jacob's 44.2 percent.

"Really what you see here is there's a very conservative contingent on issues like immigration, but there just aren't enough of them to elect a very conservative candidate," said Quin Monson, assistant director for the BYU Center for the Study of Elections and Democracy, which conducted the exit poll during Tuesday's primary.

The center's poll found that 88 percent of voters said the issue of illegal immigration held some level of importance for them in casting their vote. A majority of those polled (54 percent) said the immigration issue was "very important," while another 34 percent said it was "somewhat important."

Monson called the moderate swing voters "critical" in deciding the outcome of the primary.

Moderate voters tended to agree with Cannon's softer approach to immigration. While Jacob won a narrow victory with voters who called immigration "very important," capturing 52 percent of their votes to Cannon's 48 percent, Cannon found strong support from the groups who called immigration "somewhat important" (66 percent for Cannon), "not too important" (56 percent) or "not important at all" (52 percent).

Kelly Patterson, center director, said Cannon's attempts to create a broader appeal netted him crucial support from voters who were less concerned about immigration.

"I think what the exit poll showed was there was one issue that really mattered to a particular segment of the voters, while those voters who were less concerned with it tended to vote for Cannon," he said. "The immigration issue, while very powerful and very potent, can't mobilize enough voters to give any candidate a majority."

Cannon has backed proposals by President Bush to allow many illegal immigrants to stay in the United States under certain circumstances, while Jacob has said such proposals amount to an amnesty and has called for tougher legislation.

Recorded messages from President Bush and first lady Laura Bush, played over the phone to potential voters in the days leading up to the election, may have helped Cannon as well. The exit poll found that when voters were asked to rate the president on a scale of one to five, 65 percent gave him a four or five, and the majority of those voters supported Cannon.

Voters who had a less favorable view of the president, giving him a three or less, were more likely to vote for Jacob.