Here's a look at the top candidates vying to replace Rep. John Boehner as speaker of the House of Representatives, Rep. Kevin McCarthy (R-Calif.) and Rep. Jason Chaffetz (R-Utah). (Sarah Parnass/The Washington Post)

The Republican chairman of a high-profile House committee on Sunday shook up the race to succeed outgoing Speaker John A. Boehner, launching a challenge to the heavy favorite, Majority Leader Kevin McCarthy.

The bid by Rep. Jason Chaffetz (Utah), chairman of the Oversight and Government Reform Committee, comes amid unrest from conservatives driven by doubts that McCarthy (Calif.) will be any more inclined than Boehner to embrace the right flank of the House Republican Conference.

Chaffetz said on "Fox News Sunday" that he was “recruited” by members displeased with McCarthy’s ascent and that he would “bridge the divide” in the House GOP.

[Chaffetz to run against McCarthy for House speaker]

“You don’t just give an automatic promotion to the existing leadership team,” he said. “That doesn’t signal change. I think [House Republicans] want a fresh face and fresh new person who is actually there at the leadership table in the speaker’s role.”

Chaffetz’s remarks not only reflect tensions between conservatives and establishment Republicans, but also concerns about McCarthy’s ability to communicate with the GOP base and the public at large. Those concerns grew after McCarthy made comments last week suggesting that a House investigation into the 2012 attacks on a U.S. diplomatic compound and a CIA annex in Benghazi, Libya, stemmed from political motivations.

[McCarthy’s comments on Benghazi probe may be a political gift to Clinton]

“We need somebody who’s out there who is actually going out there and making the case to the American people, talking to the Senate about what we need to do, and going on the national television shows and winning that argument,” Chaffetz said. “We don’t seem to win the argument, and that’s a problem.”

Chaffetz has spent his four House terms working his way to the top of the Oversight Committee, a post that makes him the GOP’s prime attack dog against President Obama’s administration. He is well versed in the hand-to-hand political combat of cable news and talk radio and has become the party’s face on a variety of issues, including Secret Service failures and government funding for Planned Parenthood.

He made headlines this week after an inspector general’s report found that a top Secret Service executive suggested leaking information that Chaffetz had been passed over for an agent’s job years ago in retaliation for his committee’s aggressive investigations.

But McCarthy retains considerable advantages ahead of the closed-door GOP leadership elections set for Thursday. He enjoys a week’s head start in building support, a ready-made political infrastructure, and close relationships across the Republican conference built during his stint as the GOP’s chief House candidate recruiter ahead of the 2010 midterm elections.

A McCarthy spokesman declined to comment Sunday on Chaffetz.

In Thursday’s party elections, a speaker candidate need only win the backing of a simple majority of those voting to become the Republican nominee. But unlike other leadership posts, the speaker is chosen in a subsequent floor vote of all House members, and the House’s 246 Republicans will be under no obligation to select the party nominee.

No Democrats are expected to back McCarthy or any other Republican, so the nominee cannot afford to lose the support of more than 28 GOP members.

Chaffetz suggested that McCarthy does not have that level of support: “There are nearly 50 people and a growing number that will not and cannot vote for Kevin McCarthy as the speaker on the floor. He’s going to fall short of the 218 votes on the floor of House.”

But Chaffetz has weaknesses of his own. He has received mixed reviews of his tenure as the Oversight Committee chairman, with conservative commentators recently accusing him of squandering a hearing last week featuring the president of Planned Parenthood, Cecile Richards. And Chaffetz, who criticized McCarthy’s comments on the Benghazi investigation, has his own history of bombastic and controversial remarks.

He also played a role in a key episode that fanned conservative outrage against establishment Republicans, stripping an Oversight subcommittee chairman of his gavel in retaliation for breaking with leaders on a June procedural vote. That member, Rep. Mark Meadows (R-N.C.), went on to file a rare motion to vacate the speaker’s chair, accelerating Boehner’s departure.

Chaffetz said Sunday that he “learned from that lesson, that you’re not going to do things by cutting people off at the knees.”

“I think I’m better for it, and I think Mark is better for it, and we’re certainly good friends on this day,” he said.

Meadows agreed Sunday that bygones are bygones: “Any emphasis placed on past disagreements would be misguided and is certainly not a factor in this race for me.”

Chaffetz will audition alongside McCarthy and a third speaker candidate, Rep. Daniel Webster (R-Fla.), in closed-door meetings this week scheduled ahead of the Thursday elections. A Tuesday evening session sponsored by hard-line conservative groups, including the increasingly influential House Freedom Caucus, could be especially crucial.

Webster, a back-bencher who has emphasized the need for procedural improvements, has won some support from conservatives, but his appeal across the conference is limited. A previous speaker bid, challenging Boehner in January, garnered 12 votes.

The stakes of the speaker’s race were heightened in recent days after the Treasury Department announced that Congress must act to raise the federal debt ceiling on or about Nov. 5 — less than a week after Boehner leaves office.

An effort by Boehner to pass a debt-limit increase in his final days with mainly Democratic votes — as happened last week on a 10-week government funding extension — could further weaken McCarthy, who as majority leader is considered to be in control of the floor agenda.

Chaffetz said Sunday that “we’re just not going to unilaterally raise the debt limit” and suggested that he would take cues from members who overwhelmingly support using the deadline as leverage in spending negotiations with Obama.

“As the speaker, you’ve got to take the will of our body, appreciate and respect the process, and then go fight for that,” he said.