Which Presidential Decision Directive determines the controlling party at a suspected WMD incident?

The correct choice highlights Presidential Decision Directive 39 (PDD 39), which specifically focuses on the United States' approach to incidents involving weapons of mass destruction (WMD). This directive outlines the roles and responsibilities of various federal agencies and the framework for dealing with such incidents, defining the lead agency that coordinates the federal response and the command structure involved in a suspected WMD event.

PDD 39 is particularly significant as it designates the Department of Justice (DOJ) as the primary agency in a domestic WMD incident, emphasizing the need for a coordinated response to minimize risk and ensure public safety. This directive plays a crucial role in shaping the federal response structure to such emergencies, making clear who has control and responsibility during a crisis.

This context clarifies the importance of PDD 39 and its role in incident command during situations involving WMDs, ensuring that responders have a clear understanding of the established authority and logistical framework necessary to effectively manage such incidents.