Don't take my word for it. Listen to Mark Carney at Davos.
This is the main reason that things are different. Most presidents were reasonable in their hegemony, and Trump's naked aggression makes everyone to hedge against US.
And the competence of departments is crucial for the well functioning of the country, services high and low. (Diplomacy, war, and education to electricity and roads).
In my view it's both that the State Department, for example, is less competent than before, and that the administration is less likely to listen to the experts and Department officers than before.
(I'm not american.)
And as you go back you can see that our more contemporary actions are just echoes of the past anyhow. Vietnam was also started on a complete and malicious lie. [1] That lie then led to the deaths of tens of thousands of Americans, practically bankrupted the country (playing a major role in the events of 1971), left the country more divided than ever, and concluded with us running away from Vietnam with our tail tucked.
We didn't start the fire. It just always feels so different in the present because you don't know how things are going to turn out, so there's always the possibility that this time it might be something extraordinary as opposed to just this perpetual and never-ending self-crippling.