"Preventative Detention" -- This week's solution

Francis Morrone thinks that this article by Mark Helprin is a "must-read." I don't happen to agree but what is interesting is that the Helprin article and another piece by a fellow named Thomas Powers both discuss, to a small and large degree respectively, "preventative detention" as a means of battling terrorism.

Crooked Timber noted the Powers' article but lets it off just a bit too lightly, I think. I left this comment (more or less) there:

"What puzzles me about Powers is that it seems to me that we in the USA already have preventative detention: it’s called conspiracy law. The crime of conspiracy consists simply of “conspiring” with one other person to commit a crime.

"You don’t have to actualy commit the crime — just plan it. And the degree to which you plan it is very flexible. Some concete action must have been done -- but it might be as little, I believe, as buying a blasting cap. An aggressive prosectutor might well convince a jury that purchasing a one-way ticket is a sufficient act.

"The existence of the crime of conspiracy seems like such an obvious riposte to Powers that I wonder what, if anything, I am missing."

On futher reflection there is one thing which "preventative detention" might offer: ability to lock up an individual since conspiracy, by definition, involves two or more people.

But then, so what? The horrendous crimes/acts of war which we have seen and which we characterize as "terrorism" have almost (the unibomber the sole exception, to my knowledge) have all been done by groups -- fairly substantial groups, in fact -- of people. Conspiracy law would it seem to suffice quite nicely, at least for the actions which scare us. Let's worry about the lone terrorist when we have gotten the current situation in hand.

(And if you think that conspiracy law can be trumped by the head terrorist delegating an operation to a single person, you have missed the power of conspiracy law: the crime was comitted in that very delegation.)

What we lack is not sufficient power under law but the intelligence -- no pun intended -- to find people who are planning bad things.

UPDATE: A concerned reader tells me that I should be embarrassed -- Columbia grad and all that -- for using the word "preventative." She writes: I hate to be such a nag, but THERE IS NO WORD "PREVENTATIVE"!!!!!!! It's "preventive".

But then I go and find this definition of PREVENTATIVE. What do I do? The Powers' article uses "preventive" and so in terms of style, consistency etc I should probably use that spelling. But is "PREVENTATIVE" incorrect?

(On reflection I do find "preventative" a bit awkward as a sound. So I shall try to avoid it in the future. But, strictly speaking, was I wrong? And, more significantly, is Dictionary.com wrong?)