PROVO — Rep. Chris Cannon, R-Utah, has decided to seek a seventh term in 2008, but he'll again be forced to beat back several challenges from within his own party.

Just five months into his sixth term and 18 months from the next election, at least four other Republicans are considering taking a run at Cannon — David Leavitt, Jason Chaffetz, John Jacob and Merrill Cook.

Leavitt has formed a campaign committee and filed notice with the Federal Elections Commission that he will run against Cannon in Utah's 3rd Congressional District. Leavitt is the brother of former three-term Utah Gov. Mike Leavitt, who is now the Health and Human Services secretary in President Bush's Cabinet.

David Leavitt is better known as the former Juab County prosecutor who sent polygamist Tom Green to prison for bigamy and for fathering a child with a 13-year-old girl.

Chaffetz, a former Brigham Young University football player and former chief of staff to Gov. Jon Huntsman Jr., formed an exploratory committee five months ago to consider a run at unseating Cannon.

Jacob, who Cannon defeated last year in the Republican primary, said Tuesday it's "highly likely" he will challenge Cannon again in 2008, while former Utah Rep. Merrill Cook, who finished third to Cannon and Jacob at last year's Republican convention, said it's possible he'll join the race, too.

Cannon had $82,000 in campaign funds on hand at the end of the first quarter of this year, according to the FEC. Jacob had $1,600, but still owed more than $600,000 from last year's failed race.

Leavitt only recently filed and hasn't had to file a disclosure form. The FEC doesn't require candidates, like Chaffetz, with just exploratory committees to disclose contributions.

None of the four is put off by the expanding number of challengers.

"The failings of Mr. Cannon are so evident, obviously there is going to be a number of challengers," Chaffetz said. "All I can do is put my best foot forward and see if I'm the right messenger with the right message."

Each believes Cannon is vulnerable at the Republican convention with delegates who are more conservative than Republican primary voters.

Last year, Jacob actually beat Cannon at the GOP convention, 52 percent to 48 percent. The result forced a primary, which Cannon won, 56 percent to 44 percent.

Chaffetz decided Cannon must be replaced after observing him as Huntsman's liaison to Utah's congressional delegation.

"He has not instituted good conservative practices," Chaffetz said, pointing to fiscal discipline, limited government and ethics and personal responsibility.

Cannon defended his conservative credentials. He has the highest rating among Utah members of Congress from the American Conservative Union and the highest rating in Utah from Americans for Tax Reform.