Evidence -- What An Inconvenience!

I think I heard one of the counsel for the U.S. government suggest today (in oral argument) that one proper reason for the President's right to funnel "enemy combatants" (including U.S. citizens) into some form of military or executive detention rather than into the criminal justice system was "evidentiary concerns." Do you think we can generalize this principle -- so that the government can imprison American citizens who are suspected of wrongdoing whenever the government concludes that it does not have sufficient evidence to convict the suspected miscreants?

P.S. I can see the Statue of Liberty from my apartment building in Jersey City. As I said in a message some months ago, the Statute of Liberty was the very first thing I saw in America when the Liberty Ship in which I was traveling brought me to these shores. I naturally keep thinking of Lady Liberty.