he Central Intelligence Agency, working with American troops during the occupation of Iraq, repeatedly purchased nerve-agent rockets from a secretive Iraqi seller, part of a previously undisclosed effort to ensure that old chemical weapons remaining in Iraq did not fall into the hands of terrorists or militant groups, according to current and former American officials. The extraordinary arms purchase plan, known as Operation Avarice, began in 2005 and continued into 2006, and the American military deemed it a nonproliferation success. It led to the United States’ acquiring and destroying at least 400 Borak rockets...