While supposedly waging a war on terrorism, in reality the U.S. today finds itself embroiled in multiple civil wars: Iraq, Afghanistan and now Somalia. Some die-hard proponents of liberal interventionism would like to see Sudan added to the list. But does anyone in Washington really understand what the American military can achieve in such situations, when Sunnis are fighting Shi'ites or warlords are fighting Islamists?
Say the words civil war to Americans, and they instinctively think in terms of their own, from 1861 to 1865. A big principle (slavery) was at stake. In ethnic, religious and linguistic terms, the two sides...