(New throughout with trial closing) By Andy Sullivan WASHINGTON, Feb 20 (Reuters) - A former aide to Vice President Dick Cheney lied to the FBI because he was worried he might face criminal charges for blowing a CIA employee's cover, prosectors said on Tuesday as his perjury trial drew to a close. But Lewis "Scooter" Libby's defense team told the jury the government had failed to prove that he lied on purpose, and defense attorney Theodore Wells asked jurors to set aside politics as they weighed Libby's fate. "Don't sacrifice Scooter Libby for the way you might feel about the Bush administration or how you might feel about the war in Iraq," Wells said. Libby is on trial for lying to investigators as they sought to determine who leaked a CIA analyst's identity after her husband accused the White House of twisting intelligence to bolster the case for invading Iraq. Nobody has been charged with intentionally blowing CIA officer Valerie Plame's cover in 2003. Libby's perjury trial is the only criminal case to emerge from the investigation. Libby's attorneys say he did not lie to the FBI and a grand jury intentionally, but simply could not accurately recall conversations about Plame at a time that he was swamped with national security matters. Prosecutor Peter Zeidenberg said Libby did not want to risk losing his job after he enlisted Cheney to clear his name. "He had a choice to make -- he could tell the truth and take his chances with the investigation, or he could lie. Ladies and gentlemen, he took the second choice," Zeidenberg said. Over four weeks, jurors have heard government officials and journalists describe how Libby sought information on Plame and her husband, former ambassador Joseph Wilson, and passed it along to reporters. Jurors did not hear from Libby or Cheney. Libby says he first heard about Plame from Cheney, but forgot about her until a conversation with NBC Washington bureau chief Tim Russert jarred his memory. Russert said the two did not discuss Plame in a phone call. In his closing argument, Wells pointed out that Russert kept no notes of the call. Russert also told the FBI that he "could not completely rule out the possibility" that the two might have discussed Plame, Wells said. "You cannot convict Scooter Libby solely on the word of this man. It would be fundamentally unfair," Wells said. Another reporter, Matt Cooper of Time magazine, testified that Libby told him about Plame. Defense lawyers said Cooper's notes could indicate that Libby had told him he was "not sure if it's even true" that Wilson was married to a CIA employee. Defense lawyers called no witnesses to bolster their claim that Libby had been sacrificed to protect other White House employees deemed more valuable, like political guru Karl Rove. But Wells said a handwritten note by Cheney submitted as evidence was proof that Libby had to appeal to his boss after being rebuffed by others at the White House. "They sure didn't treat him like he was part of the team," Wells said.
