it is about all the other kinds of restraint that sex offenders are ordered rightly to live under at the end of the day. sentences in these cases include not only prison time but restraints on computer use. sometimes for decades. restraints on ability to go near children. sometime for decades. all of these things judges consider in order to effect what congress has required, which is a sentence that is sufficient but not greater than necessary. to promote the purposes of punishment. >> let me ask but that last point. you've said this a couple times now. the sentence that's congress requires. congress wanted it to be mandatory. congress wrote the guidelines in this case. they wanted they will to be mandatory. they gave the courts factors to consider to choose between the