Frank Wilkinson comments on Rubio’s attempt to straddle both sides of the immigration debate. Here he notes that Bush’s allies seem ready to use that against him:

In an interview with Bloomberg Politics, Mike Murphy, who runs the super-PAC supporting Bush’s candidacy, all but announced his intention to show the “vulnerable” side of Rubio. In the vernacular of 30-second attack ads, Rubio’s turnabout on immigration is a serious character issue.

This is one of the reasons that I remain so skeptical of Rubio’s chances in the nomination contest. Republicans have nominated pro-immigration politicians before, and they have most recently nominated a candidate who pandered shamelessly in the opposite direction, but Rubio is unusual in that he combines the worst of both. He has been very publicly on the opposite side of the immigration issue from most Republicans, but didn’t have the conviction to stick with that position when he came under attack. He showed poor political judgment with the former, and then demonstrated no political courage with the latter. While he may have repaired some of the damage with conservatives by pandering to them over the last two years, he has also proven that he easily gives in to pressure.

He was vocally in favor of the Senate immigration bill after the 2012 election, then scrambled to disavow it when the backlash against the bill set in, and one suspects that he would flip back again if he thought he could get away with it. This has the effect of making both sides in the debate wary of him and makes him too much of an opportunist. It also shows that Rubio completely failed on the one non-foreign policy issue that Rubio tried to take on. That points us to one of the other major weaknesses of his candidacy, which is that he hasn’t achieved anything.