SOMETIMES WHAT WE DON’T KNOW can indeed hurt us. This was the case in 2006, when reporters noticed significant fighting between Iraqi insurgent factions. This confused journalists and government analysts, but the prevailing attitude was that if the insurgents were fighting each other, at least they weren’t fighting us.

It turned out that the group that bore the brunt of this violence would later develop into the Anbar Salvation Front, which has proved to be one of our most important local allies in Iraq. Abu Musab al-Zarqawi, then the leader of al Qaeda in Iraq (AQI), was trying to wipe out this fledgling movement. If analysts better understood that situation, timely U.S. intervention could have thwarted Zarqawi and allowed the Anbar Salvation Front to make a difference on the ground sooner.