The Fourth Amendment affirms:
The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.
In other words, the Justice Department is not looking to discover whether an agency of the executive branch violated the law by spying on United States persons whose civil liberties are covered under the FISA laws.
Chapter 36 of U.S. Code defines a "United States person" as…
…a citizen of the United States, an alien lawfully admitted for permanent residence (as defined in section 1101 (a)(20) of title 8), an unincorporated association a substantial number of members of which are citizens of the United States or aliens lawfully admitted for permanent residence, or a corporation which is incorporated in the United States, but does not include a corporation or an association which is a foreign power, as defined in subsection (a)(1), (2), or (3) of this section.
Lamentably, public discourse over whether Messrs. Bush and Gonzalez violated the law will likely be drowned out by the noise over who snitched on them.