Sen. Chuck Hagel, R-Neb, speaks during a town hall meeting in this 2007 file photo in Lincoln, Neb. Hagel said Friday he would consider serving as Democratic presidential candidate Barack Obama's running mate if asked, but he doesn't expect to be on any ticket. (AP Photo/Nati Harnik, FILE)
Sen. Chuck Hagel, R-Neb., announces at a news conference in Omaha, Neb., in this Sept. 10, 2007 file photo. U.S. Sen. Chuck Hagel writes in a new book that the United States needs independent leadership and possibly another political party, while suggesting the war in Iraq might be remembered as one of the five biggest blunders in history. (AP Photo/Nati Harnik, File)
U.S. senators, Joseph Biden, D-Del., left, talks to Chuck Hagel, R-Neb., during a press conference at a hotel in Islamabad, Pakistan, Tuesday, Feb. 19, 2008. Biden, chairman of the Senate Foreign Relations Committee and one of several U.S. lawmakers who observed Pakistan's parliamentary elections, said Tuesday the results mean the United States can shift its Pakistan policy. (AP Photo/Vincent Thian)
In this photo provided by CBS, Senator Chuck Hagel, R-Neb.., talks to the media after appearing on CBS's "Face the Nation" in Washington, Sunday, Dec.. 9, 2007. (AP Photo/CBS Face the Nation, Karin Cooper)
In this photo provided by CBS, Senator Chuck Hagel, R-Neb.., talks to the media after appearing on CBS's "Face the Nation" in Washington, Sunday, Dec.. 9, 2007. (AP Photo/CBS Face the Nation, Karin Cooper)
In this photo provided by CBS, Senator Chuck Hagel, R-Neb., talks to the media after appearing on CBS's "Face the Nation" in Washington, Sunday, Dec.. 9, 2007. (AP Photo/CBS Face the Nation, Karin Cooper)
In this photo provided by CBS, Senator Chuck Hagel, R-Neb., talks to the media after appearing on CBS's "Face the Nation" in Washington, Sunday, Dec.. 9, 2007. (AP Photo/CBS Face the Nation, Karin Cooper)
In this photo provided by CBS, Senator Chuck Hagel, R-Neb.., talks to the media after appearing on CBS's "Face the Nation" in Washington, Sunday, Dec.. 9, 2007. (AP Photo/CBS Face the Nation, Karin Cooper)
In this photo provided by CBS, Senator Chuck Hagel, R-Neb.., talks to the media after appearing on CBS's "Face the Nation" in Washington, Sunday, Dec.. 9, 2007. (AP Photo/CBS Face the Nation, Karin Cooper)