There were legitimate moments of embarrassments during his first term, but there was enough of a presence of adults within his administration then that kept things at a simmer. At various points you had guys like Jim Mattis, Mark Esper, Steve Mnuchin, Gary Cohn, Rex Tillerson, even Mike Pompeo (who I cannot stand).... not perfect people, not people I agree with on policy, but institutionalists who understand the world order that America created post-WW2 and why it is important.
Those people are long gone from this administration... and the "institutionalists" that do exist in this new administration (ie. Marco Rubio most notably) are eunuchs who are happy to see their credibility used to launder terrible and capitulating policy.
Presidencies have come and gone, including some I've liked and some I haven't (including Trump I)... but this is definitely the first time I've felt ashamed to be an American. And we've earned every bit of ire that the Canadians, Ukrainians, or other of our allies will throw at us.