north america versus dzhokhar tsarnaev, the offense listed first is use of a weapon of mass destruction. mr. tsarnaev is being charged with the federal crime of using a weapons of mass destruction, but may mean it the way the fbi defines it, not as the military does. this does not mean that he had access to a chemical, biological, or nuclear device. it means that he used something that blew up. dzhokhar tsarnaev is a u.s. citizen. he will be tried in a civilian court. as of this evening, a senior official tells msnbc news that he can be described thus far in his initial interrogation at the hospital as cooperative. joining us now for the interview tonight is a former acting solicitor general of the united states, professional of national security law georgetown. he successfully argued the case of hamdan versus rumsfeld. professor neal katyal, it's great to have you here. thank you very much for your time. >> thanks for being here. >> so the difference between wmds as a military matter...