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In one of his first major statements on Afghanistan as Secretary of Defense, Chuck Hagel defined America's "clear and achievable" objective in Afghanistan: "to have Afghans assume full responsibility for security by the end of 2014." America's core aim has narrowed dramatically: to hand over power and withdraw.

The new goal is certainly clear and achievable. Indeed, the United States could accomplish Afghan responsibility right now, simply by leaving. The danger is that the mission turns into what Gideon Rose once called a "moon landing," or an operation designed to transport Americans far away and bring them home safely with little regard for what's left behind.