The news comes as troops pull out of Afghanistan and begin a new offensive against the Islamic State. "Hagel was not seen as a very forceful secretary of defense," NPR's Tom Bowman says.
The comments were made to a House panel by Army Gen. Martin Dempsey. Earlier, Defense Secretary Chuck Hagel said the battle against Islamic State militants would be "long and difficult."
The fight over the former GOP senator's nomination to be the next defense secretary might be bigger than any other Cabinet nomination in recent history. Chuck Hagel's friends and foes are preparing for modern combat on TV and the Internet.