(CNN) When then-House Speaker John Boehner abruptly announced his resignation in September 2015, the assumption among many people was that Kevin McCarthy would easily step into the vacuum.

After all, the genial California Republican was the House Majority Leader, the 2nd highest-ranking job within the GOP conference. The step-up seemed natural.

Less than a month after Boehner's surprise announcement, McCarthy's ambitions were dashed. A test vote within the closed Republican conference revealed that McCarthy simply didn't have enough support to win. He withdrew his candidacy. Every Republican under the sun begged Paul Ryan to put his name forward, which he eventually did.

House Majority Leader Kevin McCarthy walks out of the caucus room after he announced that he will not be a candidate for Speaker of the House in the Longworth House Office Building on Capitol Hill October 8, 2015.

Fast forward to Thursday. We are 24 hours removed from Ryan's decision to retire. And suddenly McCarthy is the frontrunner to replace him!

Huh?

At first glance, not much has changed to make McCarthy a clear favorite over House Minority Whip Steve Scalise (R-La.), who is regarded as more of a consistent conservative than McCarthy, or even a member of the House Freedom Caucus (Mark Meadows and Jim Jordan immediately jump to mind.)

McCarthy's ideological profile -- which led to some skepticism within the House Freedom Caucus last time around -- isn't much changed. ("Some conservatives seized the moment as a victory, celebrating the downfall of one of the House's fastest-rising but more moderate stars," read a Washington Post report of McCarthy's loss.)

The only thing that changed? Donald Trump is president now -- and McCarthy has gone out of his way to ensure that the two of them are tight as ticks.

You should read every word of the Post's profile of McCarthy and his cultivation of Trump but, in case you don't, here's the key bit:

"McCarthy's singular role as Trump's friend and fixer over the past year — a courtship of backslapping and flattery that has led to eye-rolling among Democrats and skeptical Republicans.

"From talks about the midterm elections at Camp David to a strategic interjection at a bipartisan immigration meeting, McCarthy, 52, has sought to position himself as Trump's indispensable man in Congress, an easygoing Republican who gets him — and likes him."

So great is McCarthy's desire to ingratiate himself to Trump that, noticing that Trump only ate red and pink Starburst candies, McCarthy ordered an aide to pick out only those colors -- them put them in a jar and delivered them as a present to Trump.

Yes, that really happened.

(Nota bene: The key to understanding Trump's likes and dislikes: He likes people who are nice to him, who cater to him and who are loyal to him. He doesn't like people who don't/aren't. The end.)

Relations between the two men have grown so warm that when rumors first began to circulate about Trump firing White House chief of staff John Kelly, McCarthy's name showed up on every short list out there as a replacement.

Which brings us right up to today, when everyone and their brother seems totally invested in making sure McCarthy is the next leader of House Republicans.

After Scalise said Thursday morning that "I've never run against Kevin and wouldn't run against Kevin," Ryan immediately seized on that statement as some sort of acknowledgment by the Louisiana Republican that he was stepping aside for McCarthy.

"I was encouraged that Steve Scalise said this morning that he thinks, you know, that after the election that Kevin McCarthy ought to be the person to replace me after the elections," Ryan said, taking at least some liberty with what Scalise was actually saying.

(Saying you wouldn't run against McCarthy doesn't mean you think McCarthy should be speaker. It means that if McCarthy isn't able to get the votes, then Scalise could step in.)

While the White House has formally avoided showing any sort of preference for a race that is six months away, you can bet all of your bank account that McCarthy has been telling every colleague he can about how tight he is with the President.

Heck, I wouldn't be surprised if he had printed out the Post profile and highlighted the Starburst story!

McCarthy and Senate Majority Leader Senator Mitch McConnell and others listen while US President Donald Trump speaks about newly passed tax reform legislation last December.

That McCarthy is currently considered the frontrunner to replace Ryan speaks to the power of Trump among the rank-and-file Republicans in the House. This is a guy they rejected two years ago because he wasn't conservative enough (among other reasons). But because he is friends with Trump and the President thinks McCarthy is a good guy, that appears to be enough for some members to sign off on the California Republican as the frontrunner to be leader.

Now, the race, as I noted, isn't likely to happen for months. Lots can change. And being the frontrunner today is less valuable than being the frontrunner in December.

Still, the resurrection of McCarthy's chances of leading his party can be traced back to Trump. And red and pink Starburst.