Historical context: During WWI, the UK financed not only it’s own war effort, but those of all of it’s allies. By the time the US joined the war, in April 1917, the UK was broke, financial reserves and credit exhausted. From that point, to the end of the war, the US financed everyone, including the British Empire.
After the war ended, the allies expected the US to forgive all the debt. Apparently, the UK had a track record of forgiving it’s allies debt, so they expected the same from the US. Nope. The US came on like a loan shark. Congress passed a law demanding the debts be paid in full, with interest, on time, or suffer being cut off from US financial markets. All of the allies “came to the table”, even the British Empire.
So now, what would anyone do, if the US seized Greenland by force? The US could threaten to cut anyone who objects off from Wall Street. I’m sure the US’ thinking would be “it’s only 55,000 people. are you going to crash your economy over them?” Realpolitik.
Steve