When I used to prosecute terrorists, it was a source of sardonic amusement to me that all sensitive evidence and other discovery was disclosed to defendants with the admonition that they would be held in contempt of court if they transmitted the information to unauthorized persons. “Imagine that,” I’d say to myself. “A guy has willingly risked death, capital punishment, and life imprisonment in order to commit mass murder, yet we think we can stop him from leaking by threatening a contempt citation?”

A Muslim registry would suffer from the same flaw. Few if any terrorists would sign up, assuming for argument’s sake that it could be enforced — and just imagine what would happen the first time the Justice Department indicted a Muslim for failing to register.

Newsflash: Jihadists lie whenever lying facilitates the execution of their missions. And they have no compunction about concealing their religion, ideology, or similar personal characteristics. Al-Qaeda, for example, has long sought American, Canadian, and European members because they can freely enter those places. These jihadists may have, say, American or British citizenship and passports, but they are not, in their own minds, Yanks or Brits. They are militant subjects of the ummah who are using a cover to infiltrate and terrorize. On this, the jihadists like to quote their prophet: “War is deceit.”