A nonwedder is someone who is unmarried. Societies that are polygamous tend to have more nonwedders than societies that are monogamous. A high prevalence of male nonwedders can predict whether civil war is likely to occur within a country or not. An article in The Economist explains this scenario very well:
"FEW South Sudanese see a link between their country’s horrific civil war and polygamy. Instead they blame greedy politicians or the tribe next door. Fair enough: corruption, weak institutions and tribalism all make violence more likely. But marital customs matter, too. Wherever polygamy is widely practised (in South Sudan, perhaps 40% of marriages involve multiple wives) turmoil tends to follow. The 20 most fragile states in the world are all somewhat or very polygamous. Polygamous nations are more likely to invade their neighbours. The polygamous regions of Haiti and Indonesia are the most turbulent. One London School of Economics study found a strong link between plural marriage and civil war. How come?"