He was a NeverTrumper for a while and talked about Trump not being able to win.
Before he was nominated, I promised to support him as the nominee and I did so. After the nomination, Levin criticized Trump for positions which Levin believed to be unsound but he did not actively work to support Hillary and he was not a "Never Trumper," rather, he stated before the election that he would vote for Trump. Levin defended his criticism of Trump on issues arguing that it was necessary to put pressure on Trump, a former Democrat, to ensure that he campaigned and governed as a conservative.
We are after all a conservative forum here and not, presumably, the Trump Republic forum.
Before the nomination it seems that we were all free, or should have been, to criticize competitors for the nomination. God knows Trump supporters did so and did so in the meanest style. After the nomination it was, of course, a different story but even then there is a difference between criticism of policy positions and support of Hillary and certainly room to criticize policy positions without being a (gasp) "Never Trumper."