America is just no good at nation building.
The Philippines, the Bay of Pigs in Cuba, the Korean War, the humiliating helicopter exit from Viet Nam, the fall of the Shah of Iran, the Contras of Nicaragua, and Iraq weren't lesson enough. Each incident ended up building dictatorships or other undemocratic totalitarian regimes in the guise of republics. The closest thing to democracy these nation building missions managed to accomplish were banana republics.
Even within its own borders, nation building among native Americans has been a dismal failure. Instead of nations, Indian reservations have become synonymous with poverty, crime, and failure.
America has forgotten the foundation that it was built on. Colonial Americans grew fed up with remote foreign mismanagement of their domestic affairs which they had managed on their own since the first day the Old World left them stranded in the New World: us versus them.
We are longer the little guys battling big guy domination. US has morphed from the we into them.