Gates chides Obama over 'absence of passion,' contrasts with Bush's style

In this April 28. 2011 file photo, President Obama stands in the East Room of the White House in Washington with Vice President Biden and then-outgoing Defense Secretary Robert Gates. (AP)

Former Defense Secretary Robert Gates on Sunday escalated his already-tough criticism of President Obama, saying the president lacked "passion" and "conviction" over his Afghanistan war strategy.

Gates spoke publicly for the first time about claims made in his startlingly candid memoir, "Duty." In the book, the former Pentagon chief claimed that the president did not believe in his own Afghanistan policy.

Not mincing words, Gates on Sunday contrasted Obama's approach with that of former President George W. Bush, in whose administration he also served.

"It's one thing to tell the troops that you support them. It's another to work at making them believe that you believe as president that their sacrifice is worth it, that the cause is just, that what they are doing is important for the country, and that they must succeed," Gates told CBS News. "President Bush did that with the troops when I was secretary. I did not see President Obama do that. As I write in the book, it was this absence of passion, this absence of a conviction of the importance of success that disturbed me."

The White House has defended the president and Vice President Biden, who was also criticized in the book, ever since excerpts from the memoir were published this past week. The White House notes that Gates spoke in favor of the strategy Obama was pursuing.

But Gates, in his book and in the interview on Sunday, complained about interference in military affairs by White House staffers. He said Sunday that "I actually think it's gotten worse."

John Bolton, former U.S. Ambassador to the United Nations under the Bush administration, told Fox News on Sunday that Gates' claims are an "indictment of Barack Obama."

Gates has faced some criticism for the book, and for speaking out against the administration he served in a short time ago. But he defended his claims on Sunday, saying he didn't think it made sense to wait until 2017, for instance, to discuss these issues.

He said he does not regret anything he's written, calling it an "honest" account.