If you believe the hype, the United States has a valuable new ally in the War on Terror: American Muslim leaders. Alas, it's called "hype" for a reason. Yes, some American Muslim groups are making a show of undertaking a sincere campaign to oppose terror, purge jihadis, help disrupt networks and thwart plots. At Christmas Day bomber Umar Abdulmutallab's arraignment this month, some 50 Muslims rallied outside the court, carrying placards that read "Not in the Name of Islam," chanting "We are Americans" and waving US flags. Majed Moughni, who organized the protest, vowed to "take our religion back" from...