The Republican race for the 3rd Congressional District is close — so close, in fact, that it's a statistical tie, a new poll shows.

Whether Rep. Chris Cannon or challenger Jason Chaffetz advance to the November final election — where either man would be the favorite — depends on which Republican can get his supporters to the polls Tuesday, a just-completed survey for the Deseret News and KSL-TV found.

Pollster Dan Jones & Associates, in a survey of registered voters completed Thursday night, found that if the election were today, 44 percent favor Cannon while 40 percent like Chaffetz. But the margin of error in the sample of 312 registered voters is plus or minus 5.5 percent.

That means Cannon's support could be as high as 49.5 percent and as low as 39.5 percent, while Chaffetz's could be as high as 45.5 percent and as low as 34.5 percent.

Jones' survey also shows that 15 percent of voters are still undecided.

"That is a high number for such a high-profile race," said Jones. "And more and more, (pollsters) are finding that those undecideds actually make up their minds in the polling booth." That not only makes it tougher to poll in a race, it also makes it difficult for candidates to identify who they want to get to the polls — for you don't want to encourage people to vote if they vote against you.

The key for both men, said Jones, who has polled in Utah for 30 years, is "who gets their real supporters to the polls."

And in that key component, Chaffetz may actually have a leg up, notes Jones. Chaffetz's voters "are more enthusiastic."

To measure enthusiasm, Jones asks the voters the degree of their interest in the 3rd District GOP race — a key measuring stick that Jones has used over the years.

And among those who said they are "very interested," Chaffetz leads Cannon 46 percent to 38 percent. Among those who said they are Republicans, Cannon leads 49-37 percent. However, independents can vote in the GOP primary as well. And Chaffetz leads among independents 46-31 percent.

The Utah Republican Party holds closed primaries. And only those registered as a Republican can vote in the 3rd District race Tuesday. However, Utah law allows an independent voter — one who is officially "unaffiliated" in their voter registration — to register as a Republican at the polls Tuesday and get a GOP ballot.

Accordingly, Jones informed those he polled about the closed primary qualifications and then asked if they were likely to vote. Nearly three of four said they were planning on voting — although Jones himself said the turnout will be much lower than that.