But there is one person who could help him out.
It's been years in the making, but McCarthy's early openness to Trump and his continued and steady relationship with President Donald Trump could be one of his best assets in his race for Speaker, a job he failed to clinch just years ago in part because of conservative mistrust.
So far, Trump has remained mum on the race but the President -- who prizes loyalty -- has never been afraid to wade into the fray and pick sides within his own party leaving plenty of room for Trump to make his mark on the House's leadership race.
A race for speaker is still months away. Speaker Paul Ryan has vowed to stay in office until January, giving McCarthy -- who has yet to formally announce his candidacy -- plenty of time to shore up support. Members are also still feeling their way around the news. Members who have spoken with CNN often say they have hardly made up their mind who they would support.
Majority Whip Steve Scalise has said he won't run against McCarthy directly, but should McCarthy fall short, it's not unfathomable that Scalise would step up.
The question within the Republican conference now is how much of an impact Trump may have on the race and whether or not it benefits the GOP to have a speaker who is in lock step with the President, a figure whose erratic style, political whims and obsession with loyalty have proven to be challenging to manage at times when trying to unite the conference and move a legislative agenda forward.
While Ryan has worked alongside Trump, forging a relationship with the President through health care and tax reform negotiations and in spite of errant Tweets, McCarthy -- in his role as majority leader-- has enjoyed an easier alliance with the President. Trump, the king of biting political nicknames like "Little Marco" and "Lyin' Ted," has referred to McCarthy as "my Kevin."
When other Republicans leaders and rank-and-file members have struggled to defend Trump's most controversial statements, McCarthy has shown little sign of distancing himself from his early decision to back Trump in the presidential race, instead playing the go-between in moments of escalating tension.
"Paul has done a very good job, but it seems that Kevin is closer to the President. They seem more comfortable with each other," said Rep. Peter King, a Republican from New York.
It was McCarthy who encouraged members and leaders to stick with Trump in the wake of the "Access Hollywood" tape when Ryan canceled a joint appearance with the then-GOP presidential nominee and top members were considering ditching Trump.
One GOP aide recalled it was McCarthy who was among the first congressional leaders to "understand and embrace" Trump's appeal with the base.
"McCarthy and Trump have similar personalities, both social animals who were drawn to elected office more by politics than by policy," the aide said noting it wasn't intended to shortchange McCarthy's policy chops.
During an inauguration lunch last year, Trump spoke out directly about the difference between his relationship with Ryan and McCarthy.
"Kevin would call me in the heat of battle," Trump told the lunch according to a Politico report. "And I'd be fighting with Paul. ... And Kevin during the heat was there for us, and I appreciate it Kevin. Thank you very much."
McCarthy's relationship with Trump has also enabled the majority leader to serve as a conduit between the administration and members of his conference when they have their own legislative priorities.
A Trump endorsement alone isn't expected to shore up the race for McCarthy, of course. Already, House Freedom Caucus co-founder and Ohio Rep. Jim Jordan has expressed interest in pursuing the speaker's gavel, a move that could be enough on its own to keep McCarthy from the number he'd need to win the speakership.
But, a Trump endorsement could force members of the Freedom Caucus -- many of whom hail from districts where the President performed well in 2016 -- into an awkward position of either defying Trump with their own candidate or coming around to a speaker they once argued was not conservative enough to lead the party.
North Carolina Rep. Mark Meadows, the chairman of the conservative House Freedom Caucus, said a Trump endorsement would certainly have an impact on the speaker's race, but that it may not be enough to settle it for a divided conference.
"It's the Republican Party. He's considered the leader of the Republican Party so his voice will certainly have a strong influence," Meadows said. "The Speaker's race is not something that will be settled by just one comment or one particular confirmation because I think it's something we have to debate and look about what we're going to be in terms of a vision going forward."
But not everyone sees Trump and McCarthy's relationship as a net positive. For moderates who may be better off distancing themselves from the President in the midterms or future elections, Trump and McCarthy's alliance could provide little room to distance oneself from a polarizing President.
"One of my concerns is how joined at the hip is McCarthy with the President," one Republican member relayed on background in order to speak freely about the leadership race. "That would be a concern of mine if I were on the outside looking in because of the divisiveness that this President brings to the table... I think the Congress should be the check and balance to the President. We should always be objective in that regard."
Leonard Lance, a Republican from New Jersey and a moderate, said he wished the White House would just stay out of the race for speaker all together.
"I don't want the White House to weigh in on this race. I think it is exclusively a matter to be decided on Capitol Hill," Lance said.
Butu that Ryan has endorsed McCarthy, Republicans argue it's McCarthy's race to lose. Still, the burden of finding 218 votes or some variation of that depending on the makeup of the GOP conference after the midterms, remains a major climb.
Lawmakers who talked to CNN confided that some in the conference are reluctant to get out and support McCarthy publicly until he has locked down a good number of votes after what happened in 2015. The last time McCarthy was up for the job, he shocked the conference and dropped out when he couldn't secure the votes he needed.
"I think there are a lot of people who were supportive of Kevin last time that want to be supportive of him this time," one GOP conference member said. "But, there are a lot of us too who don't want to have to go out on a limb and offer support and then have him not get the votes. ... He is going to have to prove a lot to people he has the votes."
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