Would non-PSI countries be subject to boardings and seizures?
PSI is not focused on countries but on shipments. Vessels of any state would be boarded only to the extent consistent with international law, e.g., upon gaining the consent of a state to board one of its flag vessels on the high seas. Any case involving a vessel carrying WMD, delivery systems, or related materials to states or non-state actors of proliferation concern could be a potential candidate for our seeking such consent, regardless of whether or not the flag state is a PSI member.
