We have tended to see jihadist terrorism as something produced in dysfunctional parts of the world, such as Afghanistan, Pakistan or the Middle East, and exported to Western countries. Protecting ourselves is a matter either of walling ourselves off, or, for the Bush administration, going "over there" and trying to fix the problem at its source by promoting democracy.
There is good reason for thinking, however, that a critical source of contemporary radical Islamism lies not in the Middle East, but in Western Europe. In addition to Bouyeri and the London bombers, the March 11 Madrid bombers and ringleaders of the September 11 attacks such as Mohamed Atta were radicalized in Europe. In the Netherlands, where upwards of 6% of the population is Muslim, there is plenty of radicalism despite the fact that Holland is both modern and democratic. And there exists no option for walling the Netherlands off from this problem.
A piece that makes some interesting points about Islamic radicalism, viewing it more as a domestic problem. It would be interesting to see some data on the social class of various participants in Islamic terrorism and possibly comparison to domestic organizations like the KKK, the ALF, and (in Canada) the FLQ.