Or can you attempt to take preventive measures?

When they are five to ten thousand miles from American soil? And are "plotting" and haven't done anything substantive>

You can just "take 'em out"? I don't think so, Don.

Of course Al Qaida & others can also say - with some justification - that they are only "taking preventative action" against the U.S. "War on Islam" or the "War on X-what-have-you".

Blind and toothless comes to mind.