lahore mosqueThe arrest of five young Americans in Pakistan who according to Pakistani officials wanted to go to fight U.S.-led forces in Afghanistan has, perhaps predictably, increased fears of radicalisation within parts of the United States own Muslim community.

It follows the arrest in Chicago of David Headley, who police say scouted out targets for last year's attack on Mumbai, and discussed with Pakistan-based militant groups plans for attacks in Denmark and India; and also comes after  last month's Fort Hood shooting in which 13 people died.

U.S. newspapers have been quick to see a pattern.  "New Cases Test Optimism on Extremism by U.S. Muslims," declared the New York Times. Or according to the L.A. Times headline: "U.S. sees homegrown Muslim extremism as rising threat."

But is there really a new trend? And how is this supposedly measured? By actual incidents? On what basis can you argue that the Fort Hood shooting was part of a trend within the American Muslim community?

Or by the numbers of arrests made? If that were true, you would have to work out whether the arrests were also the result of better policing and improved coordination between different countries' intelligence agencies.