Rubio’s counter-attacks on Ted Cruz over immigration aren’t working very well for him:

The anger toward Mr. Rubio on the right has only grown in recent days as he has taken to aggressively questioning Senator Ted Cruz’s toughness on illegal immigration, a line of attack that some Republicans say they find disingenuous.

I can understand why Rubio is eager to undermine Cruz on this issue, but because of his record he is the least credible critic of Cruz’s slipperiness. Rubio has tried to have it both ways on immigration for the last three years, which is why so many conservatives distrust him, and his main argument against Cruz is that Cruz is just like him. That’s also not very smart if the goal is to reassure conservatives that Rubio can be trusted, since the attacks on Cruz are a reminder that Rubio was a big supporter of the Gang of Eight bill that Cruz actually opposed. The attacks also remind conservatives why they dislike that bill so much, which makes Rubio’s vulnerability on this issue that much worse. Even if Rubio proves that Cruz is slippery and can’t be relied on to oppose immigration “reform,” all that he does is convince Cruz’s restrictionist and enforcement-first voters to rally behind Trump. They don’t convince any of them that they should support Rubio. There is no scenario in which hitting Cruz on immigration benefits Rubio, and by continuing the argument Rubio is likely alienating more conservative supporters that he needs than he is gaining.