The Marshall Plan spent $132 billion 2017 dollars between 1948 and 1952 to rebuild European economies after WWII. The United Kingdom received about 26% of the total, followed by France (18%) and West Germany (11%). The plan was both humanitarian and strategic.
Prior to WWII, France and the United Kingdom were the two leading colonial powers. The US was not an "also ran" prior to WWII, but the French and British umpires were still intact and functioning. After WWII, the France and the UK were no longer in a position to maintain hegemony over large parts of the world, especially the Middle East. US policy was clear after WWII: Control over Middle Eastern oil was a non-negotiable priority. It isn't that the US didn't have any oil -- we had a lot of it -- but we wanted to make sure that we had control over their customer base.
Oil and communism steered US policy for decades. I hasten to add that our competition and conflict with the Soviet Union was substantive, not merely symbolic or cultural--not that anti-communist policy was always well founded. The domino theory in Vietnam didn't hold water, but East/West competition and conflict was still quite real.
Euro-Japan-American capitalism required a clear defense around the world. We were in a position to provide it, and we did. The demise of the Soviet Union didn't solve all our problems. World-wide Capitalism still needed its champion and defender. Thus it was that we were targeted by conservative Arab/Islamist agents on 9/11. It might have made more sense for the US to attack and conquer Saudi Arabia than Iraq, but for various reasons that didn't seem like a good idea (apparently -- I wasn't included in the White House planning.)
Middle East management has become a debacle, but not because we were cruel and weak. Bad strategy was pursued, unworkable goals were embraced. It was a mess waiting to happen, and it happened very expensively.
Our conflict in the Middle East was not a culture war. It was in the defense of the world-capitalist-operation that we were there, to make sure vital energy supplies were not disrupted.
So, Australians may feel that with Donald Trump we have gone to hell in a hand basket. Don't be too critical, though. As far as I know, you all are part of the same Euro-Sino-Japan-American economic structure that the rest of us are part of, and there are no guarantees of anyone's continued prosperity. If the Economy of China contracts severely, we will all be up to our eye-balls in fresh worries.
(There is a lot of epiphenomenal cultural crap going around, and Australia is privileged to be as much a part of the crap circuit as we are.