How Civil Wars Start and How to Stop Them by American political scientist Barbara F. Walter is split into two halves. The first half documents the patterns and risk factors that lead to civil wars. It shows how civil wars in the 21st century differ substantially from prior time periods, including the US Civil War in the 19th century. While each civil war has unique aspects, Walter uses evidence from around the world to show that they follow similar patterns. In doing so, she provides tools to better identify the precursors of civil wars to stop them from occurring.

In the second half of the book, Walter focuses on the vulnerability of democracy in the US. She suggests that there are currently the same precursors that lead to civil wars. Walter argues that Trump’s presidency, including his refusal to accept the 2020 election results, have helped to erode American democracy. Furthermore, the rise of alt-right militias that target civilians and infrastructure indicates the emergence of an insurgency. Finally, the country’s systemic issues of law, race, and justice are putting it on the path toward ethnic cleansing and genocide. Walter hopes that by highlighting the political instability in the US, Americans can prevent a second civil war from happening.

How Civil Wars Start and How to Stop Them was a New York Times bestseller and has won several other awards. It has generally received positive feedback, although some critics believe the book does not provide sufficient advice to stop a civil war in the US, whereas others believe she has exaggerated the risk of a second civil war.

This guide uses the 2022 Crown edition.

Content Warning: The source text depicts acts of violence and other crimes associated with civil wars.

Plot Summary

In the Introduction, Walter uses the example of Adam Fox’s attempted kidnapping and assassination of Gretchen Whitmer, the Democratic governor of Michigan, in 2020 to illustrate how the US is not immune to political instability or another civil war. She also works to dispel popular ideas about civil wars, which typically use pre-21st-century civil wars as their basis. Prior to the 21st century, civil wars took place on battlefields and involved large standing armies and conventional warfare tactics. Today, however, civil wars are fought by guerilla warfare and militias who often target civilians and public infrastructure. These conflicts are often due to deep ethnic and cultural tensions that turn into political factions who are willing to fight for power.

Walter next turns to defining autocracy, democracy, and anocracy in Chapter 1. These categories are important because they determine how close or far away a country is from civil war. Civil wars only occur in anocracies due to weak governments and political factions based on ethnic and cultural groups. Walter argues that anocracy represents one of four risk factors that best predict civil wars. Walter focuses on the rapid democratization of Iraq and the recent phenomenon of newer and once-safe democracies, especially Ukraine, moving toward autocracies to show how this anocracy or middle zone is especially dangerous to a country’s political stability.

In Chapter 2, Walter focuses on the second predictor of civil wars: factionalism. Ethnic entrepreneurs use fearmongering rhetoric to gradually build support for political parties based on racial, ethnic, or religious identities over policies. They publicly question their rivals’ language, history, and geography. By doing so, ethnic entrepreneurs instill in their supporters feelings of fear and vulnerability. Supporters are more likely to embrace violence in this climate because they feel their way of life is under threat by other groups. Walter uses the breakup of Yugoslavia, led largely by Slobodan Milošević, as a case study to highlight the dangers of factionalism to a country’s political stability. 

Walter focuses on the dark consequences of loss of power, especially by “sons of soil” groups (e.g., the Moro in the Philippines, the Abkhazians in Georgia, and the Assamese in India), which represents the third risk factor that predicts civil wars. Loss of power helps researchers figure out who will start civil wars. However, this risk factor does not represent a trigger. Instead, Walter argues in Chapter 4 that loss of hope, particularly after failed protests and elections, is a key trigger. She uses the case studies of Northern Ireland and Syria to support this assertion. Loss of hope represents the final risk factor.

Walter next turns to how social media algorithms serve as accelerants for violence and conflict (Chapter 5). She strongly believes that social media has helped corrode democracies around the world over the last decade. She explores three interconnecting ways these platforms have helped erode democratic institutions, including through the spread of misinformation and disinformation, enabling voters themselves to elect populist leaders who stoke fear through misinformation and disinformation and increasing factionalism through divisive content.

Walter then turns her attention to the US. In Chapter 6, Walter documents how American democracy is at its most vulnerable state in over two centuries, with the country displaying all four risk factors that prelude civil wars. She pays particular attention to Donald Trump and the Republican Party, who she believes have intentionally set the US on this destructive course by exacerbating ethnic tension to maintain political power. She also presents what a civil war might look like in the US since it would be drastically different than its first civil war (Chapter 7). Walter also documents the strategies extremists use to intentionally erode democracy. While not all the strategies are present in the US, the fact that even some are raises concerns for Walter. In particular, the presence of early stages of ethnic cleansing is especially worrying.

Despite the vulnerable state of American democracy, Walter remains hopeful that Americans have the tools to fix it (Chapter 8). In particular, Americans must shore up their political institutions. Only by doing so can trust in the US government be restored. Once this happens, the US government can more effectively combat its domestic extremist problem.