Philip Klein discovers that Rubio is unreliable:

But to actually say that he would be “honored” by the chance to speak on Trump’s behalf at the GOP convention, and to downplay his previously stated problems with Trump as mere “policy differences,” is to prove the Rubio skeptics right.

That is, far from being an inspirational moral leader, Rubio has shown himself to be more of an opportunistic politician with his finger to the wind.

That appears to be true, but it raises the obvious question: what had Rubio done before now to make anyone expect him to do something different? As Klein notes, Rubio jumped on the Tea Party bandwagon when doing so helped him defeat Crist in the Senate primary, and then forgot about the supporters that had made his election possible. Once in the Senate, he backed the “Gang of Eight” bill when that seemed to be the way to advance his position within the party, and then ran away from it when the backlash against the bill came. He showed himself to be an overambitious opportunist all along, and he had already proved that he would cave under pressure, but his fans didn’t want to see it. Now he has gone from taking a self-serving anti-Trump position to accommodating himself to the nominee, and it has become impossible even for them to miss. Rubio’s “true character” was always on display for anyone that wanted to see it, and it is strange that it took this long for so many people to recognize what it was.

There was always something obviously absurd about Rubio’s attacks on Trump as a con artist. It wasn’t that he was wrong about Trump, but that he was one of the least credible people to accuse someone else of running a con on Republican voters. Rubio had just done that a few years earlier. One of the main reasons why Rubio had so little support throughout the primaries was that he had shown people on both sides of the immigration debate that he couldn’t be trusted. Opponents of the Senate immigration bill remembered that he was a leading figure on the other side, and supporters remembered how quickly he bailed on them when the going got tough. Depending on what year it was, Rubio’s position would change to suit his short-term political needs. Rubio’s critics understood that he was an opportunist because we paid attention to his record, and his fans missed it because they went out of their way to ignore that same record.