Is Mexico? I am increasingly of the view that the hard lessons of Iraq and Afghanistan will not be deliberately forgotten by the US Army as the lessons of Vietnam were, especially with the drug war in Mexico becoming ever more violent, ever closer to the US border and very much likely to spill over. As it approaches a civil war, then all the work we political scientists have done on civil war become relevant, and the stuff that spills over, like refugees and violence, is a key part of that.
I argued early in my career that ethnic conflict is not as contagious as averred. I still buy that--my distinction then and now was whether people learned from elsewhere (indirect/demonstration effects) or whether there were actually direct processes that changed the stakes, the power, etc for the neighbors. As my regular reliance on confirmation bias would suggest, I don't think people learn that much from events elsewhere simply because they will learn what they want to learn. A separatist will learn from the positive examples of separatists elsewhere and ignore the negative lessons, for instance. But the movement of people, drugs, and guns, the direct processes spawned by violence can spread yet more violence.
Given how much time and money the US spent on a distant drug war in Colombia, it is very likely that Mexico gains greater and greater attention. Of course, the ghost of past imperialism will hang over such events, but the danger to ordinary Mexicans is becoming so dire and the drug barons seem to lack the legitimacy of a Pablo Escobar (see the ESPN 30 for 30 documentary), that this COIN effort might actually have a chance. And the US commitment would be easier to justify for the long term given the proximity and stakes involved.