Personally I interpret this as a trial balloon and a true indicator of the thickness of Ridge's head.
BTW: If anyone wants to look into the Nunn- Biden (and Warner!) amendment he was talking about: AMENDMENT NO. 1251 (Senate - June 06, 1995)
"...shall not authorize arrest or any assistance in conducting searches and seizures that seek evidence related to violations of this section, except for the immediate protection of human life. "
Puts bio and chem weapons under the same exemptiom from Posse Comitatus that nuke weapons are under now.
Heck, a Governor can decide in 10 minutes that he needs federal forces to defend against such an attack- and ask for it.
No need to change the law.