Washington ? I. Lewis “Scooter” Libby’s decision not to testify in his perjury case damaged a key part of his defense Wednesday, when a federal judge ruled that his attorneys could not introduce once-classified details of his workload without Libby taking the witness stand.

The ruling by U.S. District Judge Reggie B. Walton was one of two setbacks for the defense as it finished presenting evidence in the case without calling any additional witnesses. Walton set closing arguments for Tuesday, and said the jury likely would start deliberations on Wednesday.

Offering barely two days of testimony, the defense strategy appeared to reflect a hope and belief among Libby’s attorneys that the government had failed to meet its burden of proving the defendant’s guilt beyond a reasonable doubt.

Libby is charged with covering up his role in leaking information about the wife of a Bush administration critic to journalists in the summer of 2003. He has conceded he may have misspoken to authorities, but says that is because he was consumed with more important official duties as the chief of staff and national security adviser to Vice President Dick Cheney.

During the trial, Libby’s attorneys have shown that some government witnesses had memory problems of their own, and that information about CIA operative Valerie Plame – the wife of former envoy Joseph C. Wilson IV – was known to journalists who got the information from sources other than Libby.

But the so-called busy-man defense suffered a blow Wednesday when Walton rejected a defense bid to have admitted into evidence summaries of classified materials by CIA employees who had regularly briefed Libby on intelligence matters.

The summaries were meant to buttress the argument that the weighty issues Libby was handling fogged his ability to recall details about Wilson and Plame. The materials were prepared before the trial after months of sensitive negotiations among Walton, the lawyers and intelligence authorities about what could become public.

Walton said Wednesday that he always understood that the information could become public only if Libby testified. The judge said it would be unfair to the government to now allow the jury to hear the evidence without giving prosecutors the opportunity to cross-examine the former White House aide about it.

Libby’s attorneys, Theodore Wells Jr., who announced Tuesday that neither Libby nor Cheney would be called as witnesses in the trial, said in court Wednesday that the information should still be permitted.

But Walton said to allow that would encourage gamesmanship. “If the court of appeals wants to tell me that this kind of process can occur. … I think we turn this whole process into a game. It’s too much of a game now,” the judge said.