Vice President Dick Cheney’s former chief of staff Lewis “Scooter” Libby could be behind bars within two months. On Thursday, a federal judge denied Libby’s attempt to delay the start of his sentence. Libby was convicted in March on four felony counts of making false statements to the FBI, lying to a grand jury and obstructing a probe into the leak of Valerie Plame’s identity. Administration officials outed Plame after her husband, former U.S. Ambassador Joe Wilson, publicly challenged the Bush administration’s case for going to war on Iraq. Meanwhile, Judge Reggie Walton said he had received several threatening letters after handing down Libby’s two-and-a-half-year sentence. Walton also criticized a brief from 12 law professors, including Harvard’s Alan Dershowitz, that argued Libby should avoid jail time. Walton said: “The submission was not something I would expect from a first-year law student.” Libby could still avoid prison if President Bush grants him a pardon.