Political scientist Barbara Walter explains the factors that have led to modern civil wars around the world and details how the conditions are present for a similar conflict in the United States.

Modern civil wars don't look like the ones in history books — they often have no centralized army, no leading generals, and no secession of state territory.

Carried out largely by armed guerrillas or paramilitary groups against their fellow citizens, modern civil wars erupt when identities are threatened, often as countries transition toward or away from democratic government.

As a professor of International Relations at UC San Diego's School of Global Policy and Strategy, Barbara F. Walter has researched civil wars around the world and interviewed combatants to understand what drives them.

In How Civil Wars Start, Walter asserts that civil wars emerge in predictable patterns, ones that indicate the U.S. is closer to the tipping point than we may realize.