JACKSONVILLE, Fla. — Even as Floridians digested the likelihood of their senior senator being tapped to run Donald Trump’s State Department, the question of who replaces Marco Rubio came into focus.

It’s not official yet, but it’s “very firm,” a senior source familiar with the next White House’s thinking tells The Post.

Gov. Ron DeSantis has a panoply of options open to him, from insider picks who are far from household names to state officeholders who, like him, will be term-limited in 2026 and are ready for something new.

We considered this question in July, when Rubio was being considered as Trump’s running mate, before being rejected because an all-Florida ticket would have created Electoral College problems in what was expected to be a close race.

Four months later, many of the options remain the same. Including one potentially tantalizing one.

Appointing himself.

A drawback to that?

He would be subject to an actual election in 2026 just as he would if he stayed in the governor’s office — the next election will be expedited to the midterm cycle.

And DeSantis, though he famously said when running for president that he thought he could do more in the White House for Florida than he could as governor, does not feel like he could have that effect as the junior senator to Rick Scott.

Another move could be to appoint someone who would essentially keep the seat warm until he runs again.

A candidate for that particular role: chief of staff James Uthmeier, who helped helm the campaigns to keep amendments removing abortion restrictions and legalizing recreational weed from passing.

There is precedent for the COS choice. Fifteen years ago, former Gov. Charlie Crist picked his own chief, George LeMieux, to replace Bob Martinez after the senator stepped down midterm. Crist went on to be rejected by the GOP for Rubio, then lost the election as an independent.

It couldn’t possibly go that badly for DeSantis if he wants a placeholder. He’s already ruled out a job in the Trump administration, saying he’d rather be “quarterbacking” Florida, which is just as well given Trump’s COS Susie Wiles has no reason to help him out. So as much as he might not want to be in the Senate, it’s either that or hosting a cable show if he’s shut out of the White House.

Another interesting option could also be in the governor’s mansion — though logistics present a particularly personal challenge for her.

Casey DeSantis is the most involved in policy of any of the first ladies, and she certainly would warm up to the role. But with three kids who are 8 or under, the timing isn’t right for her to take the job, especially given the governor’s demanding travel schedule. Stranger things have happened, but the family dynamic is central to the DeSantis branding, and it’s hard to imagine a nanny taking over for two years while both parents have demanding jobs.

There’s also the chance that a Florida cabinet member could get the pick, and two of them are term-limited in 2026: Attorney General Ashley Moody and chief financial officer Jimmy Patronis.

Of the two, Moody seems the more likely pick. Since Joe Biden’s 2020 election, she’s worked hand in glove with the governor in legal challenges to federal overreach on issues ranging from pandemic mitigation to border capitulation.

She is by far the most enthusiastic advocate for DeSantis of any cabinet member. And in contrast to the chilly dynamic between DeSantis and Scott that goes back to when the Naples Republican was leaving the governor’s mansion, Moody would be a genuine ally to the man who appointed her. And she would be an odds-on favorite to be elected for a full term in two years.

There also are other names worth mentioning. The ultimate olive branch to the president-elect would be a member of the Trump family; a few live in Florida, and Republican National Committee co-chair Lara Trump is being touted in some MAGA convos. And former Florida House Speaker Jose Oliva would be an interesting successor to Rubio, though it remains to be seen if he’d be as successful statewide as the outgoing senator.

Whoever the pick is, though, there will be a butterfly effect in Florida politics that reverberates through the next election.