Re: What about abuse of fair use?
RE: what happens when an American abuses copyright on an English work...
I think there are treaties with respect to copyrights in foreign countries. but take a look at the list of copyrights at the ends of movies nowadays, and you can see a bunch of legalese terms, key words, and tricky phrases with specifics for specific places on the planet.
(edit: a U.S. citizen can be held liable for U.S. laws broken while overseas - one clear example of that is what's known as 'sex tourism' and I'll leave it at that)
one of the more interesting 'fair use' exceptions (in the USA anyway) is PARODY. I did a funny parody of Kim Jong Un lookling like Cartman (respect my authoritah) using gimp to color in his suit so that it's red, and stuck a 'cartman' cap on his head (with additional cleanup needed because of his redonkulous hairstyle). Implications obvious. yet the thing I did is FUNNY. The photo was credited to fox news naturally, where it came from, and so forth. Parody. A clear 'fair use' exception under the USA copyright laws.