The Melting-Pot Theory - Why American Muslims don't blow things up.By Timothy Noah

In "The Terrorists-Are-Dumb Theory" I noted the terrible price al-Qaida paid in Afghanistan for 9/11. To repeat: Nearly 80 percent of its Afghanistan-based membership was killed in the U.S. invasion, according to journalist Lawrence Wright. Two-thirds of al-Qaida's leadership was captured or killed. The terror group's membership may now be down to as few as 200 or 300. Let's assume, as many believe, that this alone has made it very difficult for al-Qaida to stage a follow-up attack on the United States. Couldn't the job still be done by angry jihadis already living in the United States? Where are al-Qaida's sleeper cells?

This is the third essay in a series of eight exploring why the United States suffered no follow-up terror attacks after 9/11. To read the series introduction, click here.