What's the use of having all that power if you cannot defeat your enemies in Afghanistan (the Taliban). If you had to make deals with your enemies in Iraq (Sunni tribes in Anbar province, Shi'ite militias in Basra) in order to disgracefully exit. If the defeat of one foe leads to terrorism spreading across the Sahel in Sahara (militant Tuaregs fukking shyt up in Mali and feeding arms to the conflict in Northern Nigeria).
America has a lot of hard power, but unfortunately to a hammer - every problem is a nail.