Treaty...

 1917 deal

The 1917 deal was part of arrangements for President Wilson’s purchase of what are now the US Virgin Islands from Denmark for $25 million. Wilson was urged by a prominent businessman to also buy Greenland but was initially dismissive.

“Wilson said: ‘No, it’s not worth anything at all. It’s just ice. I don’t want it,’” said Høyem, who has written a book about the island.

The president was persuaded to change his mind, however, and went on to demand that the Danes throw in Greenland as part of the deal for what were then known as the Danish West Indies. Copenhagen refused and said it would only go ahead with the sale if America signed a letter saying that Greenland “is and will forever be Danish”. Wilson agreed.

“I have seen the original document myself in a museum,” Høyem said. “This means the United States has legally accepted Greenland is and will always be Danish. But Trump, it seems, has never heard that.”

It did not prevent President Eisenhower from considering another attempt to buy Greenland after the Second World War. Like Trump today, he considered it within America’s legitimate sphere of influence and vital to its security interests.

The US built military installations on the island in 1941 under an agreement with Denmark that was formalised by a treaty in 1951. The US retains the strategically important Pituffik Space Base in northwest Greenland.