The controversy over who knew what when before Sept. 11 reveals at least one thing clearly — it is very easy to get lost in a side debate. While it is important to know whether the Federal Bureau of Investigation mishandled information, that inquiry should not keep us from having the far more important public inquiry into whether the Central Intelligence Agency has learned through failure how to collect information on Islamic terrorist groups. If Washington is going to win the war on terrorism, it will have to do so overseas.