On Aug. 10, London’s Metropolitan Police Service announced that more than 20 people had been arrested in connection with an alleged terrorist plot. According to the authorities, a group planned to destroy airplanes flying from Britain to the U.S. by detonating bombs manufactured with materials that could be brought on board as part of a passenger’s carry-on luggage.

Al-Qaeda operatives hijacked and crashed four airplanes in the U.S. on Sept. 11, 2001, killing nearly 3,000 people. In July 2004, the federal commission that investigated the events of 9/11 concluded that "none of the measures adopted by the U.S. government from 1998 to 2001 disturbed or even delayed the progress of the al-Qaeda plot" and pointed out government failures of "imagination, policy, capabilities, and management."

On Aug. 29, homeland security secretary Michael Chertoff published an editorial on the Washington Post and called for broader access to passenger lists in foreign countries, writing, "All governments bear a responsibility to prevent terrorists from boarding aircraft, and information sharing is a critical way we can work together to limit terrorist mobility, screen for unknown threats and investigate terrorist cells." 62 per cent of respondents are very or somewhat worried that there will be another terrorist attack in the U.S. in the next few months.

In order to prevent terrorism at places like airports and subways, should authorities be able to single out people who look like they might be of Middle Eastern origin to search or question?

How worried are you that there will be another terrorist attack on the United States in the next few months?

• Very worried – 15%
• Somewhat worried – 37%
• Not too worried – 24%
• Not worried at all – 13%
• Not sure – 1%