Let the islamic extremists bellow (after all our troops, bases, and other buttinsky practices are gone). They can trade with us or not - their choice. They can denounce us, and fight among themselves - that is their land, not ours. It isn't even our continent, and on the far side of the one they are on across an ocean.
If they do something overt, then retaliate. Dr.Paul has already suggested letters of Marque and Reprisal. Terrorism is a police and not a military problem. If there are military problems, I don't think he would have any problem using the military to defeat a real and present and aggressive enemy. It will be healthier when it isn't wasting away bogged down fighting illusory and exaggerated threats, then trying to do anything in the midst of an undeclared civil war, or as an occupying force. The latter has never worked even from the Mexican American war.
(We negotiate with narco-terrorist warlords when we wanted the Taliban out, and the Opium flows, and Bin Laden is still quite alive - has your policy worked any better? - and Saddam and Bin Laden were our friends in the previous decades, and some in Iraq today are calling for our heads, but we need to cooperate so we do).