To amend the Floyd D. Spence National Defense Authorization Act for Fiscal Year 2001 to extend the deadline for the submission of the final report of the Commission to Assess the Threat to the United States from Electromagnetic Pulse Attack, to provide for the appointment of additional members for the Commission, to ensure the availability of funds for the Commission, and for other purposes.

Amends the Floyd D. Spence National Defense Authorization Act for Fiscal Year 2001 to: (1) extend until June 30, 2009, the deadline for the final report of the Commission to Assess the Threat to the United States from Electromagnetic Pulse Attack; (2) make the Commission chairman in charge of all Commission financial and administrative matters; and (3) provide guaranteed Commission funding for FY2008.

Authorizes the chairman of the congressional defense committees to jointly appoint up to three additional Commission members.