The flip side of that is that the USA has heavily subsidized the defenses of Europe and the rest of the world.
Not that they've asked for it - but it's difficult to conceive that Europe would have escaped Hitler or the USSR's aggressions without a lot of military spending on their behalf by the USA.
Conversely, it's difficult to conceive that the United States would have gained independence over the UK without a lot of military spending on their behalf and direct military actions by the French.
A lot, actually. Most of the European countries were so badly in debt at the end of it that it laid the foundations for the US's expanded sphere of influence, particularly as regards the Middle East and East Asia. It was also the first time that the United States had united completely with one global objective and accomplished it. It created a Global Bipolar system which ended up with unipolarity after the fall of the Soviet Union.
Not that they've asked for it - but it's difficult to conceive that Europe would have escaped Hitler or the USSR's aggressions without a lot of military spending on their behalf by the USA.