House Minority Leader Kevin McCarthy is walking a tightrope in his quest to become speaker after a much-predicted Republican wave failed to materialize on election night.

McCarthy, R-Calif., is working hard to shore up the support of his entire conference as results from Election Day continue to point toward a slim GOP majority within the House of Representatives.

“I trust you know that earning the majority is only the beginning,” McCarthy wrote in a letter to colleagues on Wednesday, announcing his campaign for speaker. “Now, we will be measured by what we do with our majority. Now, the real work begins.”

Standing in McCarthy’s way are two uncertainties: the size of the Republican majority and whether the hard-line House Freedom Caucus will grant its support.

The two are deeply interconnected. A narrow House Republican majority will empower the Freedom Caucus to extract concessions in exchange for its support. A larger majority gives McCarthy more room to maneuver without having the GOP agenda beholden to a minority of his conference.

At the moment, the Republican majority looks to be anywhere between 218 seats, the bare minimum needed to control the House, and 229 seats. The latter would constitute a sweep of all outstanding races, including some in which Democrats are favored, but still falls far short of the 60 seats McCarthy once said where possible of winning.

The Freedom Caucus, meanwhile, has more than two-dozen members and has been working to inundate new members on how to navigate pressure from leadership.

The reality is one that McCarthy has faced before. In 2015, he was seen as the odds-on favorite to replace retiring GOP Speaker John Boehner of Ohio.

McCarthy’s ambitions were dashed when the Freedom Caucus blocked his ascension. The maneuver forced McCarthy to shelve his ambitions and paved the way for then-House Ways and Means Committee Chairman Paul Ryan to become speaker.

At least one prominent McCarthy ally says the would-be speaker has learned from the experience.

“I think he learned from 2015 that you can’t be an imperious leader, like some say Boehner was, that you have to listen to all sides,” said the ally. “I wouldn’t bet against him.”

Also benefiting McCarthy is that the Freedom Caucus has changed. In 2015, the group was largely organized around its opposition to Boehner and centralized power within the speaker’s office.

Today, the caucus has no such strong animosity toward McCarthy. One of its former leaders, Ohio Rep. Jim Jordan, is one of McCarthy’s biggest advisers and boosters.

Instead of attacking McCarthy, the Freedom Caucus is set on reforming House rules to give members more power and say in the legislative process. As part of that push, the Freedom Caucus want to enact a “majority of the majority” rule that would require any legislation passed by the House to be supported by at least a majority of the GOP conference.

It also wants to permanently ban congressional earmarks, require that legislation be publicly available for at least 72 hours before a vote takes place, and diversify the steering committee that has power over committee assignments.

“The ‘leadership’ of a GOP majority – with a seven-seat margin or a 17-seat margin – has a duty to use the power of the purse to extract change,” said Rep. Chip Roy, a Texas Republican and member of the Freedom Caucus.

Supporters expect McCarthy will seek to strike a deal with the Freedom Caucus. As minority leader, McCarthy has already agreed to make oversight a top priority for conservative hardliners, a key function of the GOP majority.

A top GOP aide close to leadership told Fox News Digital that McCarthy could even wind up adopting the “majority of the majority” rule to his benefit. Given that House speaker elections take place before the entire chamber, both Democrats and Republicans are eligible to cast ballots, which means the minority in theory could vote for a candidate that wins if the majority is split.

Practically, this doesn’t happen because the majority knows it can’t be so split on its choice for speaker that the minority candidate wins. But McCarthy might push for agreement among GOP members to get a unanimous vote on the floor once it becomes clear that a majority of those members support him.

“It’s imaginable for McCarthy to go into a conference meeting and say [that] we’re going to adopt the majority rule for everything that comes on the floor of the House,” said the aide. “If you want it for legislation, then we also need it for leadership elections. And if there is a majority behind something, then the entire conference should vote for it.”

The Freedom Caucus’ inability to keep all of its members in line plays into McCarthy’s hands. As leader, he has significant ability to offer members perks and prime committee assignments in exchange for their backing.

McCarthy also benefits from being the only announced candidate for speaker. At the moment, nearly every other member of the GOP leadership has offered their support for his candidacy.

House Minority Whip Steve Scalise the most likely person with enough support to challenge McCarthy, has backed him for speaker. Scalise, R-La., is running for the No. 2 spot of House majority leader.