It wasn't just the USA. Even in the conservative Portugal of the 1960s/70s a small wave of "modern math" (as it was called here) washed over the high-schools.

It wasn't just the USA. Even in the conservative Portugal of the 1960s/70s a small wave of "modern math" (as it was called here) washed over the high-schools. I believe it was more of an experimental thing, with partial adoption - i.e. only one of the math teachers would use the new syllabus on their students, with classes six days a week (yep, back then there was Saturday morning school). All I remember now is a bit of bafflement at the set theory paraphernalia, rings and groups etc.