When Lt. Gen. David Petraeus returned from an inspection tour of Afghanistan in 2005 to brief then Secretary of Defense Donald Rumsfeld, he began with a simple image.

“The very first slide in the briefing that I gave to him was, ‘Afghanistan ≠ Iraq.’ And I then laid out to him the areas and issues in which you could compare and contrast the two countries and situations,” Petraeus recalled in an interview this month. “That comparison clearly established why, frankly, Afghanistan is a tougher nut to crack.”