My answer to Why can't the US put soldiers in Iraq instead of just using air strikes and drone strikes?
Answer by Ken Larson:
The U.S. will change its battle plans when they do not work. The Pentagon has found that boots on the ground in Iraq was a fruitless endeavor and took too many soldiers lives.
Our government is very sensitive to the echos of Vietnam, where 58,000 died, the American citizen made it clear the carnage must stop and a President departed the scene.
Technology has made other approaches available, although it certainly remains questionable as to their validity as well. In my view, military victory in this era is dead.