Is "jihad in self-defense . . . antithetical to human rights? Our answer is no." That was how Claudio Cordone, then Amnesty International's interim secretary-general, responded in February 2010 to criticism after the human-rights group made ex-Guantanamo detainee Moazzam Begg its poster child in protest of the alleged horrors of U.S. antiterror detention policies.

That's worth recalling now that British authorities have arrested Mr. Begg on suspicions of attending terrorist training camps and facilitating terrorism...