My son’s history lesson today involved ancient Rome and its involvement in the affairs/disputes/feuds of other nations. The particular episode he shared with me occurred in the 300s BC, when Rome injected itself into a war between the Gauls and the Clusines (the latter centered in modern-day Tuscany).
Instead of steadfastly minding their own business, the Romans decided to officially involve themselves in the Gaul-Clusium blood feud.
And as so often happens, things spiraled out of control. A Roman ended up killing a Gaul, the Romans refused to hand the guy over (indeed, his relatives were later promoted to the top Roman post of consul)–and by the time the episode had played itself out, the Gauls had invaded and sacked Rome.
(Of course, for the Gauls these events would also have disastrous unintended consequences; more blowback).
A lesson for our day?