Rep. Jason Chaffetz (R-UT) is planning to challenge Majority Leader Kevin McCarthy in the race to succeed exiting House Speaker John Boehner, Politico's Rachael Bade and John Bresnahan report.

Chaffetz, who's in just his fourth term in Congress, is best-known for his investigations of a series of scandals involving the US Secret Service. Conservative, telegenic, and well-liked, he chairs the House Oversight and Government Reform Committee and has never served in House leadership before. But his name made the news lately after an inspector general's report found that dozens of Secret Service officials improperly snooped on his personal records while he was investigating the agency.

Chaffetz hasn't confirmed that he's entering the race, which is slated for October 8, and his late entrance would make his effort an uphill battle. But many Republicans in Congress and outside of it are unhappy with the elevation of McCarthy, who has no discernible ideology and a tendency to say things in public that aren't on message.

That was never more evident than in an interview with Fox's Sean Hannity earlier this week when McCarthy said this:

Everybody thought Hillary Clinton was unbeatable, right? But we put together a Benghazi special committee. A select committee. What are her numbers today? Her numbers are dropping. Why? Because she’s untrustable. But no one would have known that any of that had happened had we not fought to make that happen.

For more than a year, Republicans had been insisting the select committee they formed to investigate the terrorist attacks that killed four Americans in Benghazi, Libya, in 2012 wasn't designed primarily to hurt Clinton's chances of winning the presidency. McCarthy's honesty gave Democrats, including Clinton, an opening to challenge the validity of the panel, and House Minority Leader Nancy Pelosi has since called for it to be dissolved.

The political error couldn't have come at a worse time for McCarthy, as it gave Chaffetz an opportunity to make the case that he's not the right person to lead the House Republicans.

And he pounced. In an interview with CNN this week, Chaffetz said McCarthy's remarks were "absolutely inappropriate" and that the majority leader should apologize for them.

McCarthy starts out with a big advantage

McCarthy is well-liked within the Republican Conference, and as someone who has put together the votes to win the majority whip and majority leader jobs in the past, he's got a formidable vote-counting operation in place.

But conservatives outside of Washington have been infuriated by the prospect that Boehner's departure would result in McCarthy, another establishment and mainstream legislator, moving into the speaker's job. They, and a small set of House conservatives known as the Freedom Caucus, were hoping that there would be a bigger shake-up in House leadership ranks.

So far, McCarthy's only competition has been a nominal challenge from Rep. Daniel Webster, a Florida Republican who garnered just 12 votes in a vote for speaker on the House floor in January and is in danger of losing his seat in the 2016 election.

McCarthy will have to temper the concerns of conservatives who worry that he won't be a tough enough advocate of their positions and lawmakers who worry that his lack of discipline on party message could be harmful.

Chaffetz has his work cut out for him

Chaffetz, now in just his fourth term, chairs the House Oversight and Government Reform Committee, where his highest-profile work has been in investigating a series of Secret Service scandals. It was revealed this week that Secret Service officials tried to embarrass him by breaking into his personnel records and circulating the fact that he had once applied for a job at the agency and not gotten it.

And before the Benghazi committee was created, Chaffetz was one of the lawmakers most involved in investigating that incident as a member of the Oversight and Government Reform Committee. So his criticisms of McCarthy's comments about the select committee have some credibility.

But Chaffetz made a high-profile gaffe of his own this week. At a House hearing, he displayed a comically misleading chart that appeared to show that Planned Parenthood is providing more abortions than cancer screening and prevention services, when in fact the opposite is true. After being grilled about the chart on CNN, Chaffetz doubled down, saying, "I can understand where people would say that arrows went in different directions, but the numbers were accurate."

Chaffetz, a social and fiscal conservative, is popular with colleagues, but he's never won a leadership race. And despite the frustrations of some House Republicans with McCarthy, it would be a major upset if Chaffetz won. Like McCarthy, who is in his fifth term, Chaffetz would be the fastest to rise from freshman to House speaker in more than a century.