A federal appeals court is set to hear arguments Tuesday about whether Rep. John Murtha (D-Pa.) is immune from a libel lawsuit over his comments about a 2005 incident in Haditha, Iraq.

Marine Staff Sgt. Frank Wuterich filed suit against Murtha in August 2006 for libel, defamation and invasion of privacy, alleging the Democrat “publicly and falsely accused” the Marines of “cold-blooded murder and war crimes” in the deaths of two-dozen Iraqis without facts to support that claim.

Attorneys from the Justice Department’s Civil Division representing Murtha assert the lawmaker was acting in his official capacity when he discussed the Haditha incident, making him immune from prosecution.

“On the merits, it borders on self-evident that Congressman Murtha was acting within the scope of his employment in making statements to the media concerning the war in Iraq,” U.S. Attorney Jeffrey Taylor wrote in the appeal, which also notes Murtha’s chairmanship of the Appropriations Subcommittee on Defense and his opposition to the Iraq War.

“Indeed, as this Court and others have recognized, Members of Congress in their role as the Nation’s elected leaders routinely engage the media regarding matters of interest to their constituents, and such conduct forms an inherent and wholly legitimate part of a Congressman’s job,” Taylor added.

Instead, government attorneys argued that the United States should be named as the defendant in the case and moved for the U.S. District Court to dismiss the matter.

But in September, U.S. District Judge Rosemary Collyer refused to do so, ruling that discovery in the case needed to proceed to determine whether Murtha was acting within the bounds of his post when he made those statements.

Discovery in the case has been put on hold as the Pennsylvania lawmaker appeals that ruling, including an order that he be deposed.

Wuterich’s attorneys argue that Murtha’s legislative attempts to end the Iraq War should not play a role in the case.

“This case is not about the War in Iraq or Mr. Murtha’s opposition to it,” Wuterich attorneys Mark Zaid and Bradley Moss wrote.

“What this lawsuit addresses is the irresponsible and false statements spread by Mr. Murtha, who acted outside of the scope of his employment and without any substantive basis, against a group of young Marines.”

A three-judge panel is scheduled to hear arguments in the case Tuesday. Attorneys for both parties will be allowed 15 minutes each.

In addition, Wuterich’s attorneys argue that the U.S. Court of Appeals for the D.C. Circuit lacks jurisdiction in the case, because Collyer did not reject the government’s motion to dismiss, but put the motion “in abeyance” pending the outcome of the discovery.

A second Marine, Lance Cpl. Justin Sharratt, filed a similar suit in the U.S. District Court for the Western District of Pennsylvania against Murtha in September alleging slander, defamation and invasion of privacy, as well as a violation of his constitutional right to due process and a fair trial. Sharratt has been cleared of any wrongdoing in the Haditha incident.