It can be hard to measure progress in the war on terror. How much progress has been made in Afghanistan when the Taliban no longer controls the government but has regrouped sufficiently to force a notable increase in fighting and casualties? Are we safer when Saddam Hussein is no longer paying suicide bombers but terrorists are materializing from across the Middle East to fight the American forces? Is America more secure or merely lucky when it has not been attacked but its strongest allies have? Many, if not most, of the accomplishments in fighting terrorism and Islamist extremism are either...