Earlier quoted context omitted.
Not sure I agree 9/11 was when it started. We were still cooperating with allies and other countries and still maintaining non-war stuff. Trump is when the bridge burning started and when America really lost its stature on the world stage. If it was declining since 9/11, trump took that gradual trend and sent it straight down.
Exactly the same sort of FUD was stated when Bush was president. Trump is strengthening NATO, is in the process of renegotiating several trade treaties which appear to be well received by all sides, and has made some unprecedented progress with N. Korea, while building a coalition of Arab states to counter Iran and Russia in the Middle East, plus putting pressure on Europe to lessen their dependance on Russian energy…
My impression is that Trump is negotiating completely differently than any previous US president. He's throwing extreme positions out there as a starting point, then trying to negotiate back to something reasonable. (Much of the outrage in the press is directed at his opening statements - both content and style - not at the end position.) This approach may work, if others adjust to his style. But international diplomacy is not like business negotiations, and he may wind up alienating countries that he really needs to keep as friends.