> Fearon and Laitin looked at 127 civil wars from 1945 to 1999, most often in sub-Saharan Africa and Asia. They found that regardless of how ethnically mixed a country is, the likelihood of a civil war decreases as countries get richer. The richest states are almost impervious to civil strife, no matter how multiethnic they might be — think for instance of Belgium, where Flemings and Walloons show almost no inclination to fight it out. And while the poorest countries have the most civil wars, Fearon and Laitin discovered that, oddly enough, it is actually the more homogeneous ones among them that are most likely to descend into violence.

Even the following paragraph, where another researcher challenges the Fearon and Laitin study and claims mixed groups are more prone to conflict, says that effect diminishes when the single largest group is less than 45% of the population.

(I’ve been looking at the risks of civil war recently because Brexit, on that risk to the UK I have no firm conclusions).