Trump claims that it was due to America's generosity and protection that other countries benefited and raised their living standards, while the United States itself gained nothing.
[T]he crisis of soft power risks accelerating the decline of [U.S.] power in the world, activating and speeding up centrifugal dynamics that might otherwise have taken years to fully manifest.
Trump, grandson of a German immigrant, is particularly peeved at an independent South Africa, which was the worst example of a Western supremacist-cum-colonial mindset.
What perhaps remains unresolved, is how long the American electorate will allow Trump to reduce their country into a paranoia state, an empire of appalling tantrums and ragtag diplomacy.