...to use force to stop a criminal act in progress, that's all Rand's saying. For instance, you walk up to me and point a pistol at my head. I'm within my rights to use force to stop you. The trial comes later. In the article Rand is trying to disabuse people of the false notion (pumped into them by the media) that affording "terrorists" the right to a trial somehow precludes the possibility of stopping terrorist acts in progress - which it doesn't.