Guerilla/terrorist threats.
I posted something years ago about how the terrorists were winning after we waged conventional warfare into Afgh and Iraq. We spent a shit load of money, lost almost 2x as many lives as 9/11, and in the case of Afgh specifically, the terrorists are now stronger. The case could also be made for ISIS. No idea what we are doing, but whatever it is, it's pretty obvious politics and politicians are making it worse.