For the last 70 years America, it's politicians, media, and cultural exports (holywood) has claimed to be the "leader of the free world", the "global policeman"

For the last 70 years America, it's politicians, media, and cultural exports (holywood) has claimed to be the "leader of the free world", the "global policeman", a defender of democracy, a champion of liberty, a knight in shining armour against the hoards of commumism/terrorism We've seen in the last few weeks in Kabul that that era is over, but that would be an answer to "why"