Rep. Jason Chaffetz (R-Utah) is a rising star in the Republican Party. (Melina Mara/THE WASHINGTON POST)

Saying that the battle to limit the federal budget “cannot wait,” the tea party-backed rising star explained that he didn’t want to devote his energy to a campaign — even one he’s “convinced I could win.”

“I'll continue fighting for fiscal discipline, limited government, accountability and a strong national defense. That's why I was elected.  That's what I'm doing. That’s where my passion is,” Chaffetz wrote in a statement. “Ultimately, I can spend the next 15 months doing my job, or I can spend the next 15 months campaigning to do Senator Hatch’s.”

At the end of July, Chaffetz said he would “probably” run and that “people are ready for a change.”

The decision comes as a huge relief for Hatch, who has been busy courting tea party voters, and as a disappointment for national groups who hoped to oust the six-term incumbent.

“We wish Congressman Chaffetz the best in his congressional campaign and in his continued service as one of Utah's representatives,” Hatch campaign manager Dave Hansen said in a statement. “Senator Hatch looks forward to continuing to work together as a delegation to find solutions to the critical issues facing Utah and our nation.”

The powerful conservative groups Club for Growth and Freedomworks have both targeted Hatch.

Utah Republicans hold a nominating convention at which 3,500 party delegates vote for their preferred candidate. If a candidate takes 60 percent of the delegates’ votes, he or she takes the nomination without a primary.

Three-term incumbent Sen. Bob Bennett (R) was ousted by Mike Lee in just that way last year; Lee now sits in the Senate. (Chaffetz took a pass on that race too.)

As recently as two weeks ago, sources said that Chaffetz believed he had the votes to take the nomination at the convention. But if Hatch were to survive that test, the two would face off in a primary where the senator had a huge financial advantage and was polling ahead.

“For not being in leadership, [Chaffetz is] treated very well by the leadership,” said Utah Republican strategist Jeff Hartley. “Hatch has been very skillful at making it difficult for Chaffetz to raise money. He would be giving up a sure thing for a tough fight.”

Chaffetz’s decision also puts the spotlight on state Sen. Dan Liljenquist (R), who is still considering a bid and is now more likely to run.

A number of politicians had already expressed interest in Chaffetz’s House seat. State Sen. John Valentine, state Reps. Chris Herrod and Stephen Sandstrom, and former state Reps. Craig Frank and Morgan Philpot will all have to direct their ambitions elsewhere.