Some lawmakers, such as Sen. John McCain (R-AZ), have not taken issue with the content of the book itself, but with the timing of its publication -- while the President is still in office. Gates said he didn't feel that the timing was an issue at all.
"I didn't think that waiting until 2017 to weigh in on these issues, and in a comprehensive and comprehensive way, made any sense," he said.
Gates also said there was no issue talking about Obama's concerns about how the U.S. approached the war in Afghanistan.
"My one concern was that over the course of 2010 and early 2011, the President began to have his own reservations about whether it would all work. And I think that's not an unfair thing to say," Gates said.
Correction: This post originally stated that the interviewed aired on CBS' "Face the Nation." The interview first aired on "CBS Sunday Morning."