Just after the 1991 Persian Gulf War against Iraq, huge tents were erected in Saudi Arabia near the barracks of U.S. military personnel. Inside, day and night, Saudi imams sent by their government lectured the GIs about Islam and made aggressive pitches to convert them. Saudi officials had promised that the discussions would touch only on Arab culture. But within months, about 1,000 soldiers, and perhaps as many as 3,000, converted to Islam -- the largest surge of Muslims ever into the U.S. armed forces. "It was quite aggressive," said David Peterson, then the military's top chaplain in the region....