Sen. Marco Rubio (R-Fla.) (Alex Wong/Getty Images) Sen. Marco Rubio (R-Fla.) (Alex Wong/Getty Images)

The story on immigration reform remains very simple: Republicans, at some point, will have to decide whether they want it to pass or not. Not whether they’ll vote for it — most of them won’t. But Democrats are happy to supply the bulk of the votes on this one, so all that matters is whether Republicans choose to let them or not.

That comes up again with Sen. Marco Rubio (R-Fla.), one of the Gang of Eight who drafted the Senate bill, suddenly announcing he will walk if border security amendments that would unravel the compromise legislation are not adopted in the full Senate:

Well, I think if those amendments don’t pass, then I think we’ve got a bill that isn’t going to become law, and I think we’re wasting our time. So the answer is no.

As Ed Kilgore notes, the story here appears to be all about Rubio’s presidential ambitions, with support for comprehensive immigration reform potentially spiking Rubio’s shot at the Republican nomination.

Meanwhile, over in the House, Rep. Tom Price (R-Ga.) says that it’s “highly unlikely” that anything with a path to citizenship can win more than half of House Republicans, as Sahil Kapur reports.

Does that mean that immigration reform is dead? No, it doesn’t.

Again: Immigration reform doesn’t need all that many votes from Republicans. Without Rubio, it probably has only about 60 in the Senate, instead of about 75 — but 60 is all it needs, and if Republicans really want it to pass it doesn’t even need that many. Remember, the bill had the support of every Democrat in Judiciary plus two “Gang of Eight” Republicans, Jeff Flake and Lindsey Graham, and also got the vote of Orrin Hatch.  Losing Rubio could still leave the bill likely to retain the support of more than half a dozen Republicans, along with almost every Democrat. As for the House, it’s no surprise that most Republicans will oppose the bill if it gets to the floor; the real question has been from the start whether Speaker John Boehner would bring it up, not whether it has the votes if he does.

What Rubio’s apparent defection could mean is that the vote in the Senate will be a lot less overwhelming. But that only really matters to the extent that it puts pressure on the House. And what really matters in the House probably isn’t media pressure, but the basic calculation by mainstream conservatives about whether passing a bill is better than not passing a bill.

And the truth is that there’s really no other way. The reality has always been that a lot of Republicans would not vote for any kind of path to citizenship at all, so Democrats were always going to have to supply the bulk of the votes for any imaginable version of comprehensive immigration reform.

In other words, what it all comes down to is that Republicans have to make a choice. If they want to spike comprehensive immigration reform — perhaps because they fear anti-immigrant voters in primaries, perhaps because they fear newly (eventually) enfranchised immigrant voters — they can do that, simply by not bringing up the bill in the House. If they want to pass the bill — perhaps because they fear angering large numbers of Latino and other immigrant or immigrant-sympathetic voters — they can do that, too; for the most part, all they’ll need to do is get out of the way.

We still have no idea which they will do. But once again, it’s probably safe to ignore all the rhetoric (and, ultimately, even the votes) that they throw to one side or the other. What this is all going to come down to is a choice: Bring a bill to the House floor, or not. And Boehner will do it if the bulk of his caucus wants him to do it — even if they also plan to vote against it and to denounce him publicly for doing so. If, however, they really want the bill to die, then it will die.

So while there may be any number of relatively small provisions that can be negotiated, what it’s all going to come down to is the choice that Republicans make. And for that, we’ll just have to wait and see.