In his new book, Gates writes that the Vice President "has been wrong on nearly every major foreign policy and national security issue over the past four decades."
Hayden said that Obama is grateful for Gates' counsel as Defense Secretary, but that he welcomes a wide range of opinions form his cabinet.
"The President deeply appreciates Bob Gates' service as Secretary of Defense, and his lifetime of service to our country," Hayden said in the statement. "As has always been the case, the President welcomes differences of view among his national security team, which broaden his options and enhance our policies. The President wishes Secretary Gates well as he recovers from his recent injury, and discusses his book."