Immigration is demagogued. I’d have to see what Romney proposed before I could tell you whether I thought it was rational or not. At some point last year, he managed to get some support from the anti-illegal-immigrant anti-amnesty crowd. But he certainly wasn’t the best candidate on that issue.
IMO Romney pushing “immigration reform,” after the various monsters that have gone by that name, is, from a conservative point of view, tone deaf.
And after a candidate flips, or appears to flip, too many times on an issue that voters really care about, he is likely to lose their trust.