Senility is no defense.

Lawyers for Rep. John P. Murtha will appeal a recent ruling advancing a defamation lawsuit brought against the Pennsylvania Democrat by a U.S. Marine under investigation for killing Iraqi civilians.

Justice Department lawyers representing Murtha on Nov. 16 filed notice that they planned to appeal a federal district court judge’s Sept. 28 ruling allowing the lawsuit to proceed and ordering Murtha to give sworn testimony in the case.

Why are Justice Department lawyers representing Murtha? If anything, they ought to be prosecuting him.

Here’s the answer:

If the court determines Murtha indeed was acting in his official capacity, the U.S. government could be substituted as the defendant — a move that would effectively neuter the case because the federal government cannot be sued for libel.

But Wuterich’s lawyer, Mark S. Zaid, said Monday that the deposition now likely will be delayed, pending a determination from the U.S. Court of Appeals for the District of Columbia Circuit. The court will have to determine whether it has the jurisdiction to hear Murtha’s appeal at this stage or if it should wait until a lower court determine’s the fate of Wuterich’s lawsuit.

If that defense flies, then Dollar Bill Jefferson really was just keeping his cash cool.