I am very sorry to hear of his passing. I liked much of his material, especially including Parliament of Whores, Give War a Chance, Eat The Rich, and Don't Vote! It Just Encourages the Bastards. (Eat The Rich should be a required high-school textbook.) I have quoted him many times over the years and written about him from time to time. He was entirely willing to support military intervention by the US, but his libertarianism made him very suspicious of nation-building. I think he proved out there. The Colin Powell "If you break it, you own it" doctrine is a cute line, but turned out to be a terrible foundation for policy. O'Rourke pointed out many times that what we said we were going to do at the outset of a war seldom turned out to be what we actually did.
Good quotes of his in general. Favorites of mine I have quoted in the past:
I usually vote with the Republicans because they have fewer ideas. But not few enough.
The purpose of voting is not to elect great men, but to vote the bastards out.
There are a billion people in China. And every man-jack of them wants a Buick.
I have heard him speak to small groups here in NH, where he eventually moved, down near the central border near where we vacation. He did not like Trump at all in 2016, believing he would get us into more unnecessary wars - which was pretty much my worry as well. I don't think I heard PJ recant that, but I might have missed it. He was less in the public eye after 2015, and I did not seek him out. Toward the end in early 2020 I heard him deploring the ridiculous spending that Donald was doing while still pretending to be a friend of conservatives, but I never heard what he thought after that or about that election. I felt the same way about the $, and still do. I voted for the bastard, but the way conservatives could overlook the trillions he was forking over because they felt good about his "owning the libs" irritated me. Somehow the populists forgot that we are always voting for the lesser of two evils - and he was - and got excited about him instead. Never a good sign.
Despite losing his perspective and endorsing Hillary in 2016, I think history will be kind to him.