Scooter Libby arrives at U.S. Federal Court in Washington on Feb. 15 (AP Photo/Pablo Martinez Monsivais)

Former Vice Presidential Chief of Staff Lewis Libby decided against testifying or summoning his former boss and in so doing may have saved the White House from prosecution in connection with leaking the identity of a CIA agent.

Associates said Libby decided at the last minute not to testify or call Vice President Dick Cheney to testify for the defense. They said Libby, who served as Cheney's national security adviser, was warned that either step could further involve the White House in possible criminal proceedings over the disclosure of the identity of CIA Agent Valerie Plame in 2003.

"Libby decided to fall on the sword for Cheney and the White House," one associate said. "If he or Cheney would have testified, it would have seriously compromised the vice president and the White House."

The decision resulted in a trial that barely lasted three days. The defense—opting not to call senior White House officials, including then-White House spokesman Scott McClellan or White House Communications Director Dan Bartlett—rested its case on Feb. 14 in a decision that stunned presiding Judge Reggie Walton.

The associates expressed deep pessimism over Libby's chances of acquittal in his trial in federal district court in Washington. They said federal prosecutors purposely selected him for prosecution while making deals with other administration officials who leaked Plame's identity.

"Not going to protect one staffer and sacrifice the guy that was asked to stick his neck in the meat grinder because of the incompetence of others," Cheney wrote in a note after the White House protected such staffers as Deputy White House Chief of Staff Karl Rove.

Libby has been charged with lying to an FBI agent and grand jury as well as obstructing an investigation into the administration leak. Closing arguments were scheduled for Feb. 20.

"Once it was clear that Libby wasn't the leaker, the prosecution looked for other charges," said a former colleague of Libby’s. "But the main charge was disproved."

The defense has proven that three senior administration officials provided reporters with Plame's identity. The defense has accused Special Prosecutor Patrick Fitzgerald of making deals with administration officials and reporters in his prosecution of Libby.

Until February, the associates said, Libby was intent on testifying and even planned to call Cheney to the stand. But within a week of his trial, they said, Libby, in what has angered the prosecution and judge, decided against being subject to cross-examination in the interest of protecting the administration.

On Feb. 14, Walton said he was misled by the defense that Libby would testify. The judge prevented Libby from employing classified evidence meant to prove that his incorrect answers to investigators were based on faulty memory rather than deliberate deceit. Libby had argued that he was preoccupied with national security issues when questioned by the FBI.

"My absolute understanding was that Mr. Libby was going to testify," Walton said. "My ruling was based on the fact that he was going to testify.”

Libby's chief defense lawyer, Theodore Wells said his team recommended that the presentation be cut short. Wells said Libby agreed that neither he nor Cheney would testify.

The key prosecution witness has been NBC newsman Tim Russert. Russert has denied a telephone conversation in 2003 in which he purportedly told Libby that all reporters knew that Plame worked at the CIA.

The defense has argued that Fitzgerald agreed not to prosecute Russert in exchange for his cooperation against Libby. Unlike other reporters, Russert was not summoned before a grand jury, rather in violation of procedure, was allowed to testify in an interview alongside his attorney.

"His [Russert’s] credibility, it seems to me, is crucial to this case," Walton said. "He's probably, if not the most important, one of the most important witnesses."

Sources close to Libby said the White House has been closely following the trial. They said Fitzgerald was believed to have prepared a formidable cross-examination against Cheney that could have involved him in the Plame leaks. Fitzgerald has said that Libby learned of Plame's identity from Cheney himself.

The prosecution said Libby was told in 2003 that Plame, the wife of anti-Iraq war critic and former Ambassador Joseph Wilson, worked for the CIA, and later leaked this to reporters. Under oath, Libby said he had never discussed this with reporters and learned of Plame through Russert.

Two other reporters, Judith Miller, formerly of The New York Times, and Matthew Cooper, formerly of Time magazine, testified that Libby raised Plame's employment at the CIA. The defense responded that the reporters were incorrect.

John Hannah, a former deputy to Libby and now Cheney's national security adviser, testified for two hours on Libby's responsibilities. Hannah said Libby, known for having a terrible memory, was swamped with crises, including Iran, Iraq, North Korea and Turkey.

"He was the key person talking about and helping advise the vice president on issues of homeland security," Hannah said.

Witnesses brought by the defense asserted that at least three other senior administration officials leaked Plame's identity. They included Rove, White House press secretary Ari Fleischer and Deputy Secretary of State Richard Armitage.

Fleischer has received immunity from prosecution in exchange for cooperating against Libby. Armitage and Rove were never charged. Rove testified five times before a grand jury.

"Libby was an important staffer," Wells said. "But Karl Rove was the lifeblood of the Republican Party."