Vance is an opportunist. He does or says whatever he needs to say. For example, In 2016, he was a "never Trump guy"

It means that he'll suck up to whoever he needs to suck up to in order to advance his own interests. His spinelessness is how he managed to get where he is.

With Trump's midterm implosion, an opportunist is free to attack Trump era policies. He can potentially thread the needle. He can argue that as VP, his job was to support the president's agenda wholeheartedly, even if he disagreed with it. He can point to his 2016 "never Trump" creds to show that he didn't think Trump was right for office, but that the public disagreed, and supporting the will of the electorate was more important than his personal beliefs.

Now that the public has turned so hard against Trump, Vance can claim he is now obligated to act in accordance to his constituents.

Opportunist doesn't necessarily mean "truly evil". The only people around for him to suck up to will be blue, or out of power.