Wouldn't it make much more sense to devote some effort and expense to promoting the values of the enlightenment? In particular, devoting some educational effort towards eradication of irrational beliefs. Why not actually treat Islam (and Scientology, and Christianity) as the mental equivalent of a public heath hazard, where those who believe need to be helped to overcome it?
I think we make a serious mistake in our public discourse, by considering that:
violent minority = extremists = misinterpretation of scripture vs. peaceful majority = mainstream = correct interpretation of scripture.
whereas it would be more intellectually honest to consider:
violent minority = literalists = correct interpretation of scripture vs. peaceful majority = reformists = those who wilfully mis-interpret their scripture.
In other words, while almost all humans (of all faith and of none) are decent, good, tolerant peaceful people, they are decent to the extent that they discard their holy books, not to the extent that they follow them. The holy books themselves are beyond redemption, and should be considered to be "on the side of the devil".
Consider the spectrum of belief: (a)Secular humanist ---- (b) "Moderate" religion ----- (c) Extremist religion.
Position (b) involves belief in gods, prophets, and veneration of "perfect" scriptures. Position (c) is a very small step beyond, namely to actually read those scriptures, already considered perfect, and interpret them the literally, as they are written. So, if we want to prevent Islamic terrorism, the most effective argument is not detailed discussion of which Koranic verse overrides which other one (an argument which the moderates can never win), but instead, to argue for the wholesale abandonment of holy books.
Education, science, secular values, and human rights are the most potent weapon we have against faith, and yet politicians refuse to deploy them! If we took the money from the security services, and put it into schools, I think it would be far more effective.