How does it affect you though?
I live in a country which needs strong allies to keep covetous eyes off of it, among a group of nations who still needs strong allies to avoid foreign Powers trying to split it up and dominate them separately; and the US is, in my opinion, a very good ally in that sense.
Some say it isn't, but I'm not convinced that the deals we could strike today with other superpowers can outweight what we have now (even with all the difficulties and things to address).
The US retraction has indeed already exposed the EU to new, disruptive foreign interferences.
But the real effects will become apparent later. Some of them may even be positive, like maybe the EU will stop fiddle about and push more towards unification, also for self-defense (and we are talking about moves that have started in early 2017 and have still not had an effect that the Average citizen can touch). A scenario where this is necessary is not a solid, stable, peaceful scenario, though, which is probably the major risk of this US retraction.
Things are changing fast, in this world; the Pax Americana worked from 1991 because of the incredible imbalance in strength; but this is changing, and more than two players with similar strength spell instability.
The US retraction and weakening bond with its allies mean a weakening US. More Powers are incresing in strength at the same time, and will try to cut those allies from the US to get them over to their own side, or to have them alone to be preyed. Think of the recent moves: the EU, Africa, Korea, South Asia...
What the US didn't need was an isolationist-leaning president.
Which doesn't mean that he can't also do good things, but surely not in foreign politics.
To prevent questions: would Clinton have done better? She would have probably gone too far the other side. But she was surely not the one that competiting Powers would have chosen...