The French Revolution shifted conflict from wars among princes to wars among nations.

Evidence

In 1793 as R. R. Palmer put it, “The wars of kings were over; the wars of peoples had begun.” This nineteenth-century pattern lasted until World War I. — Samuel P. Huntington, The Clash of Civilizations and the…, 143

Categorization

• CANDY: A quotable one-liner tracing the evolution of Western war: religious, then dynastic, then national.