Sambanis in NYT on civil war in Iraq (probably req a “borrowed” TimesSelect®™ password):

Civil wars are defined as armed conflicts between the government of a sovereign state and domestic political groups mounting effective resistance in relatively continuous fighting that causes high numbers of deaths. This broad definition does not always distinguish civil wars from other forms of political violence, so we often use somewhat arbitrary criteria, like different thresholds of annual deaths, to sort out cases. Depending on the criteria used, there have been about 100 to 150 civil wars since 1945. Iraq is clearly one of them.