Casus Belli
Definition: act of war; cause for war
This is from the literal Latin. It’s related to the “just war doctrine,” meaning it refers to an act in which war is a (subjectively) justified response.
Why I Looked It Up
I have the photo of a book page in my notes, but I don’t remember where it’s from. It discusses the run-up to the Iraq War:
The president…directly [invoked] the fourteen-year-old Kurdish tragedy at Halabja as a casus belli…