Probably nothing that would matter at this point. Trump vacillating between supporting Ukraine and supporting Russia is consistent with this. He’s angling to be the peacemaker, but doesn’t know how. Every time Russia does something he doesn’t like, he starts giving Ukraine a little more. That doesn’t end the war, so he needs to get Russia back to the table by being nice to them. There isn’t much more to it than that. Just an idiot who thinks he deserves a Nobel Peace Prize.

Whatever blackmail is there may have mattered in 2016, but it doesn’t matter now.