In an interview published in Foreign Policy magazine, Defense Secretary Robert Gates says he plans to step down early next year. Gates, who was appointed to the job by George W. Bush, says he agreed to stay on when President Obama asked because, "in the middle of two wars, kids out there getting hurt and dying, there was no way that I was going to say, 'No.'" So why is he looking to leave now?

His work is done: "Gates arguably has done more to reshape the modern military than most of his predecessors," says Peter Grier in The Christian Science Monitor. He has killed or downsized 33 weapons systems, including the Air Force's cherished F-22 Raptor and the Army’s ambitious Future Combat System. He has fired top generals and "replaced them with leaders attuned to his desire to build more-flexible forces." In short, his efforts to transform the military are now essentially complete.
"Why would Defense Secretary Robert Gates want to retire?"

He'll have to retire after his last, great battle: Gates still hopes to downsize "the bloated defense bureaucracies," which are bigger today than they were during the Cold War, says John Barry in Newsweek. That battle will "consume every gram of political capital Gates has built up in Congress" and alienate many of his fellow Republicans. Gates will probably win, "but he’ll emerge as damaged goods, and he knows it."
"Why Gates seems set on a 2011 departure"

He's bluffing: No matter what Gates told Foreign Policy, says Craig Whitlock in The Washington Post, he's not acting like a man looking to retire. Just last week, he has worked hard "to free up $100 billion for weapons systems and other purposes in the next five years." And next year the top Army job and the chairman of the Joint Chiefs of Staff are slated to be replaced, and major decisions are due on Afghan troop levels. Gates isn't the kind of guy who would walk away and leave such important calls to the new guy.
"Gates retiring? Don't bet on it"