That would certainly not be either morally justified, nor would the results be happy. However, that's not the issue.
The issue is the fact that terrorists will be able to acquire and deploy nerve gas, biological weapons and perhaps even nuclear bombs. Those who are willing and able to acquire and use such devices in order to commit mass murder must not be allowed to live. It's them or us. It's that simple.
I don't think you'll find many libertarians who disagree with this from sourcery :
The issue is the fact that terrorists will be able to acquire and deploy nerve gas, biological weapons and perhaps even nuclear bombs. Those who are willing and able to acquire and use such devices in order to commit mass murder must not be allowed to live. It's them or us.
We need to keep our eyes on the prize.
Find and prosecute -- with extreme prejudice when advisable -- those who fit sourcery's description above.
Avoid, to the fullest extent possible consistent with the objective, the taking of truly innocent lives.
These cannot be accomplished either quickly or through conventional military means.
Libertarians are more skeptical than most conservatives about the likelihood that those in the U.S. decision-making hierarchy are likely to pursue these objectives wisely, justly, honestly or with that single goal in mind -- not necessary here to catalogue the many possible competing interests which might enter into decision-making and thereby lead to inappropriate adventurism.
Can we agree we should:
1) Do whatever is actually necessary to build, or rebuild, the information-gathering apparatus necessary to identify those who are mortal threats to our country.
2) Do whatever is actually necessary to build or rebuild the covert operations apparatus necessary to aggressively deal with those threats.
3) Accept that it will take years to accomplish these goals and resist the temptation to engage in exploits designed primarily to demonstrate that we're "taking names and kicking a$$e$. "
It's in the actuallys that the problems and the fears of most libertarians lie, IMO. I'll bet the vast majority of libertarians on FR would be far more comfortable with aggressive action if the decisions were in the hands of annalex, sourcery, Lysander, Taliesan, Uriel1975, A.J. Armitage, and a dozen or so more I could name, than in the hands of a decision-making apparatus which has established a consistent pattern over the past century of so often taking actions with which we disagree on the periphery of or as a by-product or secondary objective of a stated policy initiative which we generally support. It's often not the stated goal or the publicly known aspects of these operations with which we disagree, but the unstated and the secret.
Whom can we trust? I hope it's GW and associates, but I'd feel a lot better if the likes of Robert Mueller, Glen Fine, Lee Radek, Norman Minetta, Richard Armitage -- and yes, Colin Powell and John Ashcroft -- were not in the mix.