“For the Kremlin, it’s now harder to define the enemy". Yup, with trump in place, I can understand that. 
It's maybe too obvious to state, but I'll do it anyway:  Everybody in the world outside his immediate family, can become trump's enemy and then his friend again, in the space of a day or 2 tweets, whichever come first.
I wouldn't mind Putin being confused by trump, but when trump himself does 180s, 360s on every subject every day so he seriously confuses himself  - major problem.
The only positive side I can see right now is that he'll decide tomorrow that he never said anything about banning transgenders from the military. Since it's taken 30 seconds to type this, he may already have done so.