Writing in the op ed pages of the Washington Post, former Attorney General Michael B. Mukasey clearly explains it all to you why the U.S.'s gentle treatment of the Christmas Day almost terrorist as a mere criminal was wrong.

There was thus no legal or policy compulsion to treat Abdulmutallab as a criminal defendant, at least initially, and every reason to treat him as an intelligence asset to be exploited promptly. The way to do that was not simply to have locally available field agents question him but, rather, to get in the room people who knew about al-Qaeda in Yemen, people who could obtain information, check that information against other available data and perhaps get feedback from others in the field before going back to Abdulmutallab to follow up where necessary, all the while keeping secret the fact of his cooperation. Once his former cohorts know he is providing information, they can act to make that information useless.