Is Rubio trapped on immigration reform?

So here is the precise rock and hard place between which Rubio is stuck. In months of painstaking negotiations with the gang of eight, he agreed to the existing language. But now that he sees the pushback from the right (“Rubio’s Folly” and all that), he is certain—as, indeed, he has already signaled in various comments—that the Senate can “improve” the bill. This almost surely means tinkering with the beginning of the RPI process.

But too much of that will certainly mean some Democrats will turn against the bill. A Senate source suggests to me that it could be a big enough number to be decisive to the bill’s chances. The RPI process, another person watching all this closely told me yesterday, is the key to the whole thing. It will make the term “illegal,” now a contested little piece of rhetorical real estate, superfluous (at least as pertains to everyone here before the above-noted date). It will bring those people into civic life—and make them taxpayers, by the way—and as such is pretty much the central point of this entire exercise.

Yesterday, Rubio’s office leaked to Roll Call a list of changes to that process he’d like to see. There are five of them. They all seem fairly secondary to me, but you can be pretty certain that if the Democrats are basically okay with them, the Republicans probably won’t be, and vice-versa.