I do not often get requests for comments about immigration policy anymore. That's fine, as I haven't published much research on immigration per se in over a year. However, I guess I am still on a few journalists' list of people to call when they need a quote from an academic on immigration and public opinion.
The reality is that Republican attitudes on immigration are complicated. Yes, a majority of Republicans appear to support some pathway to legalization -- though not citizenship -- provided immigrants meet certain qualifications and border security is also improved. However, most are not particularly sympathetic to undocumented immigrants.
Curiously enough, while a majority of Republicans appear to support some form of legalization, a larger majority said that offering legalization would reward bad behavior. A majority also think immigrants are more of a liability than an assett for the country, and a plurality of Republicans want immigration decreased -- more than twice as many Republicans want it decreased than want it increased. They would certainly not endorse Bush's statement that entering the United States illegally qualifies as "an act of love."
So how can we make sense of this? My guess is that question wording plays some role here. The question from the relevant poll (it's the recent Pew study) asked respondents whether immigrants should be able to stay in the country provided certain (unspecified) requirements are met or whether they should not be able to stay. I suspect different question wording would have provided different results. For example, if the question had used the toxic word "amnesty," we probably would have seen very different results. The alternative to legalization, that the undocumented should "not be allowed to stay," was also kind of ambiguous. What does this mean? Does it mean mass deportations? Or does it mean the status quo, in which undocumented immigrants do not have an easy means to acheive legal status, but most do not really face a high probability of being deported? If the alternative was explicitly "mass deportations," we would probably have seen an even higher percentage support legalization.
I would be interested to see the partisan divide regarding which requirements undocumented immigrants should meet in order to qualify for legal status. My guess is that the divide is pretty big, and the average Republican would make some pretty stringent demands.
The question still remains why, if Republicans are, on average, still generally opposed to high levels of immigration, do a majority of them support legalization? My own guess is that they are simply tired of the issue. There is furthermore the perennial claim that opposition to legalization is killing the GOP's shot at winning Hispanics. Many Republicans in the electorate are probably willing to hold their nose and support legalization in the hope that doing so will improve their party's electoral fortunes. I actually think the degree to which Hispanics will back the GOP if the party becomes pro-immigration has been overstated. Immigration is not the only issue where Hispanics are, on average, more progressive than non-Hispanic whites, but that is an issue for another day.