PDD-39, Presidential Decision Directive 39, the U.S. Policy on Counterterrorism, was signed January 21, 1995, by President William Jefferson Clinton. "PDD-39 defines policies regarding the Federal response to threats or acts of terrorism involving nuclear, biological, and/or chemical material, and/or weapons of mass destruction (NBC/WMD)." 
Section 3 states: "We shall have the ability to respond rapidly and decisively to terrorism directed against us wherever it occurs, to protect Americans, arrest or defeat the perpetrators, respond with all appropriate instruments against the sponsoring organizations and governments and provide recovery relief to victims, as permitted by law."
- PDD-39, with portions redacted and as declassified January 24, 1997, posted on the Federation of American Scientists webpage.
- "Federal Response Plan Notice of Change," Federal Emergency Management Agency, February 27, 1997.
- An Unclassified Synopsis of PDD-39, Department of Justice.