Posner on Law and Terrorism

From Judge Richard A. Posner's Not a Suicide Pact: The Constitution in a Time of National Emergency:

A belief of many civil libertarians that both jostles uneasily with their suspicion of police and prosecutors and, more important, reflects a misunderstanding of modern terrorism is that since acts of terrorism are criminal we should leave it to the criminal law to deal with them. So David Cole and Jim Dempsey want "intelligence" confined to "the collection and analysis of information about a [known] criminal enterprise" with the aim of using that information as evidence in a public trial of the criminals. They do not acknowledge that a public trial, or any trial, may come too late. The rather casual attitude of the FBI and other police forces toward ordinary crime - accepting that a great deal of it will occur and being content to limit the crime rate by apprehending and prosecuting a fraction of criminals, thus incapacitating some and deterring some others - is misplaced when it comes to fighting terrorism. Because terrorist attacks are potentially so destructive and also because many terrorists are undeterrable, the emphasis of public policy shifts from punishment after an attack occurs to preventing it from occuring. The line between punishment and prevention blurs when preparatory activity is criminalized, as it is in the criminal law concepts of attempt and conspiracy. But civil libertarians want to limit the prosecution of preparatory activity, lest it result in punishment of harmless acts, as in the old English crime of "compassing" (imagining) the death of the king. A limitation to completed acts of terrorism, however, would make the criminal law an even less adequate response to terrorism than it is.