An Army psychiatrist at Fort Hood, Texas, allegedly kills 13 of his service mates. A Pakistani immigrant tries to set off a car bomb in Times Square. An American convert to Islam murders a military recruiter in Arkansas.
Each reportedly subscribed to a radical strain of Islam that, they believed, directed them to defend their faith by killing Americans. These attacks, along with the dozens of home-grown plots we know about, raise obvious questions about dangers that may be emanating from the American Muslim community of 2 million to 3 million people.