In this May 12, 2008 file photograph, Vice President Dick Cheney and Republican congressional candidate Greg Davis wave to the audience at an election rally in Southaven, Miss. Davis who is involved in a heated race for the seat, has run ads in the majority white district, trying to tie his Democratic rival with Barack Obama's former pastor, seen by some as an anti-white firebrand. (AP Photo/Rogelio V. Solis, File)

David Addington, chief of staff for Vice President Dick Cheney, waits to testify on Capitol Hill in Washington, Thursday, June 26, 2008, before the House Constitution, Civil Right, and Civil Liberties subcommittee hearing on the legal rights for detainees at Guantanamo Bay. (AP Photo/Susan Walsh)

David Addington, chief of staff for Vice President Dick Cheney, left, and John Yoo, a law professor at the University of California at Berkeley, right, wait to testify on Capitol Hill in Washington, Thursday, June 26, 2008, before the House Constitution, Civil Right, and Civil Liberties subcommittee hearing on the legal rights for detainees at Guantanamo Bay. (AP Photo/Susan Walsh)

David Addington, chief of staff for Vice President Dick Cheney, waits to testify on Capitol Hill in Washington, Thursday, June 26, 2008, before the House Constitution, Civil Right, and Civil Liberties subcommittee hearing on the legal rights for detainees at Guantanamo Bay. (AP Photo/Susan Walsh)

David Addington, chief of staff for Vice President Dick Cheney, testifies on Capitol Hill in Washington, Thursday, June 26, 2008, before the House Constitution, Civil Right, and Civil Liberties subcommittee hearing on the legal rights for detainees at Guantanamo Bay. (AP Photo/Susan Walsh)

Demonstrators wearing prisoners' clothing and masks depicting, from left, US President George W. Bush, Vice-President Dick Cheney and U.S. Secretary of State Condoleezza Rice, participate in an anti-Bush protest in Rome, Wednesday, June 11, 2008. President Bush arrived in Rome Wednesday for a three-day visit which includes a meeting with Pope Benedict XVI on Friday at the Vatican. (AP Photo/Andrew Medichini

In this May 9, 2008 file photo, former CIA officer Valerie Plame speaks in Chicago. A House committee chairman said Tuesday he is seeking more documents from the CIA leak probe because Vice President Dick Cheney's former chief of staff made a significant disclosure to the FBI that warrants further congressional follow-up. (AP Photo/M. Spencer Green, File)

In this May 9, 2008 file photo, former CIA officer Valerie Plame speaks in Chicago. A House committee chairman said Tuesday he is seeking more documents from the CIA leak probe because Vice President Dick Cheney's former chief of staff made a significant disclosure to the FBI that warrants further congressional follow-up. (AP Photo/M. Spencer Green, File)

Vice President Dick Cheney delivers remarks during the Gerald R. Ford Journalism Prize luncheon, Monday, June 2, 2008, at the National Press Club in Washington. (AP Photo/Manuel Balce Ceneta)

Vice President Dick Cheney, accompanied by his wife Lynne Cheney, reacts during the Gerald R. Ford Journalism Prize luncheon, Monday, June 2, 2008, at the National Press Club in Washington. (AP Photo/Manuel Balce Ceneta)