I used to think Rubio embracing amnesty was terrible for Jeb. If Bush ran in 2016, I assumed, he’d run as a loud and proud fan of immigration reform, vowing to give the GOP’s wealthy business class all the cheap, legal labor it could handle. Rubio joining the Gang of Eight suddenly meant that there would be two candidates in the race who could fill that niche — and Rubio was younger, less likely to alienate conservatives, more likely to appeal to Latino voters, and unencumbered by “Bush” baggage. He out-Jebbed Jeb! In hindsight, though, Rubio going all in for amnesty and angering righties in the process was great news for Bush: it meant that if Jeb jumped in and started gobbling up all the fatcat money in the donor class that Rubio was counting on (especially from Florida fatcats), conservatives would merely grumble a bit and shrug. Imagine how white-hot outrage on the right would be right now if Rubio had maintained his tea-party bona fides, stayed away from the Gang of Eight, and then been bigfooted on the eve of the primary campaign in his own backyard by a well-connected centrist Republican relic of the pre-tea-party era — named “Bush,” no less. We’d be in full revolt.

I wonder if Rubio, by pounding Obama (and Rand Paul) on Cuba, will earn back enough affection from righties to spark a small revolt against Jeb’s march through the donor class after all.

While the vast number of influential figures in the Republican Party have not yet said who they support, a slew of political operatives and donors in Florida, including former state party chair Van Poole and ex-RNC finance chairman Al Hoffman, all told the Tampa Times over the last week they would choose Bush over Rubio if the two ran against each other. Several of them suggested Rubio should not run, since he would be fighting important political influencers in his own home state.

Meanwhile, Mel Sembler, who was the Republican National Committee’s finance chair from 1997 to 2000 and then served as George W. Bush’s ambassador to Italy, told the Newark Star-Ledger that he was an “admirer” of Christie but will opt for Bush…

“I’ve been associated with the family since 1979,” Sembler said, referring to the Bushes. “I have a history with them and I will continue that history.”

Brian Ballard, a Florida lobbyist who was on Mitt Romney’s finance committee in 2012, told NBC News, “I think Jeb’s time is now. Marco’s time may be now, but it may be later.”

“The people that were big Marco fundraisers? Bar none, all of those people are Jeb people first,” GOP consultant Ana Navarro told the Tampa Times. “We love Jeb, and we love Marco. But we’ve loved Jeb longer.” That’s fine establishment logic — nothing signals that the party is young, dynamic, and forward-looking quite like backing George W. Bush’s brother because he’s been around longer than Rubio has. (Actually, knocking off a smart, creative policymaker like Mike Lee for some old, corporate-friendly GOP timeserver in Utah might signal it better.) But wait: Doesn’t Rubio have a track record of defying expectations and jumping in to challenge RINOs with strong establishment backing? Charlie Crist was supposed to win Florida’s Senate race in a walkover in 2010; Rubio ended up chasing him right out of the party before crushing him on election day. A bunch of politicos I follow on Twitter mentioned that over the weekend as a reason to think Rubio might run against Bush anyway. The problem , though, is that Rubio will have no natural base in a presidential primary like he did against Crist four years ago. Back then, there were loads of conservatives in Florida looking for an alternative to Crist, especially with tea-party sentiments against RINOs at high tide. Rubio was the only game in town. Next year, there’ll be loads of conservatives nationally looking for an alternative to Jeb — and able to meet their needs by choosing from any one of half a dozen strong candidates, starting with Cruz, Paul, and Walker. Running as a “Not Jeb” in 2015 is a smart approach, but more than half the field will be following it. How does Rubio distinguish himself in that case? Hard to believe relations with Cuba will matter so much to righties next year that it’ll propel him, damaged as he is by amnesty, ahead of someone like Walker on the right.

There may be only one man alive, my friends, capable of derailing the Bush express. Can you feel it?

One wild card in donor calculations is the uncertain intention of Mr. Romney. Spencer Zwick, who ran Mr. Romney’s fundraising operation in 2012, has been meeting with Republican donors in recent weeks to gauge their appetite for another bid, according to people familiar with those talks. Many of the meetings have been initiated by donors hoping to see Mr. Romney run again.

“If Gov. Romney were to run, one thing is for sure: The financial support would be there in a big way,” said Mr. Zwick, who said he fields regular calls from Republicans who want the former Massachusetts governor to enter the race.

National polls show that a substantial well of support remains in the party for Mr. Romney. Confidants say the former nominee isn’t actively exploring another presidential bid but hasn’t ruled it out.

“Party leaders and major donors are reaching out to Mitt, asking him to run again,” said Kent Lucken, an adviser on Mr. Romney’s 2008 and 2012 presidential campaigns who traveled with him this past fall. “Will he do it? I don’t know. He has been a bit taken aback by how enthusiastic people are.”

That’s why Jeb got in early, I assume — with Zwick twisting arms for Romney, Bush needed to show donors he was serious about running. The tough question if you’re a Republican millionaire trying to decide which flavor of vanilla to choose here is who has more of a downside. Is it the guy who’ll spend half the campaign trying to explain away George W. Bush’s mistakes, and who’s already inspired a sense of mutual loathing with the conservative base? Or is it the guy who’ll spend half the campaign trying to explain away his own mistakes from the 2012 campaign, and who’ll surely need to do an about-face on his “self-deportation” proposals on immigration from the last time he ran? The national electorate already knows what it thinks of Romney whereas Jeb has time to make friends; on the other hand, choosing Jeb likely means a second dynastic Bush/Clinton election at a moment when all the energy in politics, right and left, is towards populism. Nominating Romney doesn’t solve that problem, needless to say, but it doesn’t make it worse like nominating Jeb would.

Exit question: Can’t grassroots RINOs and conservatives dispense with all this crap and come together for Scott Walker already? We all know that’s where this is headed. Walker/Rubio or Walker/Jindal will be just fine for both wings of the party — in practice, I suspect, even more so for centrists than for conservatives.