An Israeli army reservist’s dream vacation in Brazil ended abruptly last month over an accusation that he committed war crimes in the Gaza Strip. Yuval Vagdani woke up on January 4 to a flurry of missed calls from family members and Israel’s Foreign Ministry with an urgent warning: A pro-Palestinian legal group had convinced a federal judge in Brazil to open a war crimes investigation for his alleged participation in the demolition of civilian homes in Gaza.

A frightened Vagdani fled the country on a commercial flight the next day to avoid the grip of a powerful legal concept called “universal jurisdiction”, which allows governments to prosecute people for the most serious crimes regardless of where they are allegedly committed.