The Post's article reports the defamation lawsuit is based on public comments Murtha made outside his scope as a congressman:
Attorneys for Frank D. Wuterich, 26, argue in court papers that Murtha tarnished the Marine's reputation by telling news organizations in May that the Marine unit cracked after a roadside bomb killed one of its members and that the troops "killed innocent civilians in cold blood." Murtha also said repeatedly that the incident was covered up....
... statements made by members of Congress generally are protected under the "speech or debate" clause in Article I, Section 6, of the Constitution. But legal experts said the clause grants immunity only for what lawmakers say in legislative proceedings and does not apply to news releases, speeches and other
