Secretary of Defense Robert Gates. (Photo:DoD/Cherie Cullen)

Defense Secretary Robert Gates plans to retire next year, saying he wants to see through the current push in Afghanistan.

In an interview with Foreign Policy magazine published Monday, Gates said he wants to retire before the 2012 presidential election season gets underway. Gates has led the Pentagon through a major shift in overall strategy beginning near the end of the Bush administration and continuing when he agreed to stay on as the defense secretary under President Obama.

Gates says his strategy in Afghanistan was based on watching the Soviet Union fall apart fighting in Afghanistan. “Once the Afghans come to see you as an occupier, you’re toast,” Gates said. But he came to believe that the Soviets failed because they had killed 1 million Afghans and displaced 5 million more, turning the whole country against them. “Clearly,” Gates told FP, “none of that is what we were about in Afghanistan.”

Gates’s new strategy for Afghanistan, championed by former Afghan war commander Stanley McChrystal, is based on the idea of avoiding that fate. McChrystal wanted to add 40,00 troops, but use them as part of a strategy that emphasized building relationships with the locals and giving them control of the situation. That strategy is being carried on by Gen. David Petraeus, McChrystal’s successor.

The FP article continues:

In the end, Obama decided to send 30,000 extra troops (McChrystal had recommended 40,000) and adopt a somewhat scaled-down version of a counterinsurgency strategy, while also beginning to withdraw some of those troops by July 2011. What-if games are dubious enterprises, but it’s not unreasonable to infer that, had Gates come into those meetings as skeptical as he’d been before his summertime conversion, the emerging consensus — and Obama’s decision — might have tilted toward a smaller deployment and a less ambitious strategy.

Today, as the last 10,000 of the “surge” troops arrive in Afghanistan amid growing doubts in Washington and elsewhere about the war, Gates is optimistic that the strategy for Afghanistan will work. McChrystal’s firing did little to change the overall approach because Obama replaced him with Petraeus, who knew the plan and terrain well. “I see the process of transition in Afghanistan being similar to Iraq,” Gates said in our interview, “in which we’re in the lead, then we’re partners [with Afghan security forces], then they’re in the lead, then we’re in tactical overwatch, and then strategic overwatch. And that will take some time.”