"First of all, since when has the US NOT put its own interests first? Never."
.
Not sure that is a balanced view.
.
In 1938 FDR and people like Carl Vinson saved the world by authorising the programs that would wi the war they could see was coming.
.
In 1946 Harry Truman, George Marshall, Dwight Eisenhower, Chip Bohlen, and others, did something that no other victorious power in world history has ever done:
.
They could see that the peace was failing, so America reached out and lifted up not only its failing allies, but also its former enemies, protected them and raised them up out of misery.
.
It was among the least selfish and least sordid acts of any great power, ever.
.
The true greatness of America was not shown in her undoubted overwhelming military might, but in the moral strength of her boundless generosity.
.
It saved the world.