Explanation: Vietnam invaded and overthrew the brutal Khmer Rouge regime in Cambodia. Under the Khmer Rouge, ‘intellectuals’ were murdered en masse, amongst other groups. Even glasses were dangerous - because it was a little signifier that you MIGHT be one of those dangerous intellectuals in need of purging. It was… quite gruesome.

Textbook example of a justifiable causus belli and proper way to do invasion.

Finally someone without an opinion! /s

A good movie on the subject: https://en.m.wikipedia.org/wiki/The_Killing_Fields_(film)

Also a first-hand account: https://www.goodreads.com/book/show/386580.Survival_in_the_Killing_Fields

Just gonna leave this helpful NYT article right here…