In the MCU, Captain America is the leader of the Avengers, who were operating for SHIELD (at least until its destruction), which itself was under the command of a mysterious "World Council".
But, at the same time, Captain America started his superhero career as an American soldier. He is still a symbol for Americans and a symbol of America outside his country.
What is Captain America's true allegiance? The movies’ dangers are so huge that the interests of the USA coincide with those of the world, but is it stated somewhere in the movies which side he would choose if the USA had interests that were in contradiction with those of the rest of the world?
I am mostly interested in answers about the MCU, but I am not sure there is conclusive information in it. In that case, I would be happy to hear about the comics.