His staff and supporters will be quick to remind you that he’s always said he prefers the “security first” option. Okay, but his preference didn’t stop him from co-sponsoring a mammoth comprehensive bill championed by Democrats like Chuck Schumer. In fact, let’s compare Rubio’s rhetoric now versus then. Here he is in June 2013 describing the Gang of Eight bill:

Rubio, responding to the concern that legalization might be delayed and therefore be subjected to the policies of future administrations: Let’s be clear. Nobody is talking about preventing the legalization. The legalization is going to happen. That means the following will happen: First comes the legalization. Then come the measures to secure the border. And then comes the process of permanent residence. What we’re talking about here is the system of permanent residence. As for the legalization, the enormous majority of my colleagues have accepted that it has to happen and that it has to begin at the same time we begin the measures for [the border]. It is not conditional. The legalization is not conditional.

That was the fatal flaw in the bill. If you could somehow arrange a comprehensive deal in which enforcement not only comes first but has been measurably improved before legalization begins, you’ll get some (but not all) border hawks to sign on. A comprehensive bill that makes security its top priority, ensuring that this is the last mass amnesty that America ever undertakes, is worth considering. A bill that legalizes illegals before anything concrete has been achieved on the border isn’t. That’s a recipe for more mass illegal immigration and more amnesties down the road. A nonstarter.

And yesterday, speaking to NPR, Rubio seems to have realized it:

Rubio told Inskeep its political failure came about because his fellow senators did not heed his own warnings to impose border security measures strict enough to satisfy House Republicans.

Rubio said that for major legislation to pass “any time in the next decade,” immigration problems will have to be tackled in steps: first, greater border security, then modernizing the legal immigration system. Only after those goals are accomplished will the country be able to decide “what to do with the 11 or 12 million human beings that are in this country illegally,” he said.

He reiterated the point in a speech this morning:

RUBIO says he does not see immigration reform passing in next decade unless border security handled separately and first

— Kelly O'Donnell (@KellyO) July 23, 2014

I don’t know how else to read this except as a formal repudiation of comprehensive immigration reform — coincidentally, just as 2016 speculation is heating up! (When asked about that by NPR, he said he’d make a decision about running in the next few months.) I’ve been skeptical that he’ll run, either because Jeb Bush will jump in and bigfoot him out of the race by stealing his Florida base of donors and advisors or because Rubio will conclude that he can afford to wait. But there’s no ignoring the evidence lately that he’s thinking hard about it. He’s running away from amnesty ahead of the primaries; he’s starting to swipe at Hillary for being old news; he’s giving thoughtful, well received economic speeches aimed at middle-class voters, among whom Hillary may be especially vulnerable; and he’s trying to move — a little bit — towards the center on social issues. Here’s a passage on gay marriage from today’s speech that denounces discrimination against gays and assures SSM supporters that he respects their position while also reassuring conservatives that he’s on their side. If the embedded text is too small for you to read, click here and it’ll take you to a bigger version.

here’s the full gay marriage portion of Rubio’s speech pic.twitter.com/8AcSvWuitH

— Jon Ward (@jonward11) July 23, 2014

If Jeb has already decided to run I assume word would have gotten back to Rubio by now, either from Bush himself or from their mutual acquaintances. The fact that Rubio’s moving full speed ahead with his own campaign makes me think Bush really is undecided at this point or, maybe, that he’s quietly decided against running but is keeping that quiet for the moment. Other Republicans seem to have the same impression: Lately Rob Portman has made some noise suggesting he might be eyeing a run, and since he’d run as a moderate (he’s a rare Republican who’s pro-gay marriage, remember), he must have reason to believe there’ll be some space in that niche for him. Which, maybe, means no Jeb. Hmmmm.