It’s one thing to be too soft on immigration. I’d bet that, deep down, most of the serious GOP presidential contenders are; some are soft even on the surface.

Nor is Rubio the only GOP contender to have flip-flopped on the issue. Neither Jeb Bush nor Scott Walker has been a model of consistency.

But Rubio is the only serious contender (I don’t consider Lindsey Graham serious) who (1) reached across the aisle to collaborate on amnesty/path to citizenship legislation, (2) was rolled by Chuck Schumer and company into sponsoring a bill he no longer stands behind, and (3) helped smear key opponents of his legislation and, when called on this, did not disavow the smear.