In 478 BC, the Athenians and a number of other Greek city-states entered into a military alliance to deal with the ongoing Persian menace. At first, the idea was that each member of the alliance would provide a fixed number of ships for a fleet. Over time, it became more convenient for the allies to provide money instead of ships; it was paid into a central treasury in Delos. The Athenians subsequently moved the treasury to Athens and started using the money for their own purposes, including the construction of the Parthenon. The alliance had evolved into a protection racket, usually described by historians as the Athenian Empire.
Does this sound a bit familiar? Do you suppose that Donald Trump, that well-known classical scholar, is aware of this story? Could his plans for NATO be based on the Delian League?
No. Trump got his ideas from gangster movies. The result is the same, however.