For American-Pakistanis, the bomb plot instilled not so much fear but embarrassment. “Back in the 1960s, Pakistanis were always held in great esteem. They were seen as making very valuable contributions to America. That deteriorated after September 11,” commented Arshad Qureshi, a 70-year-old actuary after saying his evening prayers at a neatly manicured Maryland mosque. Qureshi refused to criticize Americans who voice suspicions about Pakistan. “If you go to the root causes, I would blame ourselves,” he said.

Ashraf Qazi, chairman of the Council on Pakistan Relations, an advocacy group for Pakistani-Americans, believed that Americans understood that only a few terrorism suspects have emerged from a community estimated at more than half a million.

“I don’t think the public in general believes in guilt by association,” Qazi said by telephone from Michigan, where he runs a health care company.

“You’re really at a loss for words when you look at this situation,” he said. “I think this also shows the need for us to be more vigilant.”