JUDGE SAYS MATT COOPER'S TESTIMONY MAY BE IMPEACHABLE

Judge rules reporters must surrender some documents in Libby case.

All of the news organizations had asked Walton to review the materials sought by Libby — including e-mails, drafts of articles and reporters' notes — in hopes of convincing him that they were not relevant and that the defense was on a "fishing expedition."

During that review, Walton said, he found "a slight alteration between the several drafts of the articles" Cooper wrote about his conversations with Libby and the reporter's first-person account of his testimony before a federal grand jury.

"This slight alteration between the drafts will permit the defendant to impeach Cooper, regardless of the substance of his trial testimony, because his trial testimony cannot be consistent with both versions," Walton wrote.

It is unclear from Walton's ruling what those inconsistencies are.

Tags: Matt Cooper, Judith Miller, Scooter Libby, Plame case