On average, a civil war with interstate intervention was 300% longer than those without. When disaggregated, a civil war with intervention on only one side is 156% longer, while when intervention occurs on both sides the average civil war is longer by an additional 92%. If one of the intervening states was a superpower, a civil war is a further 72% longer; a conflict such as the Angolan Civil War, in which there is two-sided foreign intervention, including by a superpower (actually, two superpowers in the case of Angola), would be 538% longer on average than a civil war without any international intervention.