That's because perhaps the biggest debate within the GOP on immigration isn't about policy, it's about politics. On the pro-reform side, Republicans like Rubio and John McCain argue that immigration reform is a matter of survival for the party -- a necessary prerequisite for courting the growing Latino vote before must-win states like Texas turn blue. As Rubio is fond of saying, "It's very hard to make the economic argument to people who think you want to deport their grandmother." Jeb Bush devotes an entire chapter of his book towards convincing Republicans that Latinos can be won over if the conversation just shifts to education, religion, and the economy.
On the other side are reform critics like Rush Limbaugh and the National Review's editorial board, who argue that immigration isn't worth antagonizing white conservatives because Latinos will never vote Republican even if it passes.
"Take away the Spanish surname and Latino voters look a great deal like many other Democratic constituencies," read a National Review editorial in January. "Low-income households headed by single mothers and dependent upon some form of welfare are not looking for an excuse to join forces with Paul Ryan and Pat Toomey."
Putting the rhetoric about welfare mothers aside, there is strong polling evidence that Latinos side with Democrats strongly on economic issues as well, giving Republicans less of an opportunity to dislodge them. Some Republican consultants have suggested setting a modest target of consolidating conservative Latinos, with an optimistic goal of hitting the mid-40s overall in the long term.
But on the pro-reform side, a poll this week by Latino Decisions exclusively surveying Latino voters found that immigration had moved well ahead of the economy in terms of its relative importance to the community. In addition, respondents said they would be far more likely to vote for Republicans if they backed a path to citizenship for the undocumented population.
Data is still scarce on the post-election state of the Latino vote, but if Rubio can't move the needle in polls even as immigration reform approaches passage it could intensify fears among rank-and-file Republicans that they're about to grant legal status to a giant new Democratic voting bloc. For that reason alone, it's worth keeping an eye on the 2016 crosstabs even if it's three years out from the GOP primaries.