ARRIVING IN BRITAIN by air the day after two men crashed a gasoline-laden Jeep Cherokee into the main terminal at Glasgow's international airport, and a couple of days after two car bombs were discovered in the heart of London, I was surprised by how calm everybody was. Apart from the prohibition of passenger drop-off and pickup next to the terminal building at Birmingham Airport, everything was as usual. Men and women in Muslim garb mingled in the crowd with perfect tranquillity, expecting neither violence nor even verbal reproach. Was this a sign of the admirable tolerance of British society, or...