Foreign Intelligence Surveillance Substitution Act of 2007 - Requires a federal or state court to substitute the United States for an electronic communication service provider with respect to any claim in a covered civil action if the Attorney General certifies to the court that either: (1) the service provider did not provide the alleged assistance; or (2) the assistance alleged to have been provided was in connection with an intelligence activity involving communications authorized by the President between September 11, 2001, and January 17, 2007, and designed to detect or prevent a terrorist attack, or activities in preparation for a terrorist attack, against the United States. Requires the alleged provider assistance to be described in a written request or directive from the Attorney General or the head of an element of the intelligence community to the electronic communication service provider indicating that the activity was authorized by the President and determined to be lawful.
Requires a federal or state court, upon receiving such a certification, to: (1) substitute the United States for the electronic communication service provider as the defendant as to all claims designated by the Attorney General in the certification; (2) dismiss all such designated claims against the provider; and (3) enter a final judgment relating to those claims.
Provides that the electronic communication service provider shall remain as a defendant if the Attorney General's certification states that not all of the alleged assistance was provided under a written request or directive.
Provides that, in a covered civil action in which the United States is substituted as a party-defendant, any plaintiff may serve third-party discovery requests to any electronic communications service provider as to which all claims are dismissed.