Donald Trump has said he wants the US to acquire Greenland. The US president-elect says this step is "absolutely necessary in the interests of national security and freedom in the world." When he announced his interest in buying Greenland from Denmark during his first term of office, Danish Prime Minister Mette Frederiksen thought it was simply "absurd." The matter seemed settled.

Now, even before he is sworn into office, Trump suddenly doesn't rule out using economic or military pressure to bring Greenland under US control. The territory is geographically part of North America, but politically part of Europe. Various European heads of government have expressed their horror at the idea that the strongest member of NATO could annex the territory of an alliance partner by force — in the way that Russian President Vladimir Putin has taken over swathes of Ukraine.

German Chancellor Olaf Scholz drew this parallel without mentioning Trump by name: "The principle of inviolability of borders applies to every country, regardless of whether it lies to the east or west of us."

Moscow promptly tried to use Trump's threat to justify its own actions in Ukraine. Kremlin spokesman Dmitry Peskov suggested consulting the population of Greenland about what they wanted, pointing to the referendums — widely seen as shams — held in regions in eastern Ukraine that Moscow has annexed.

The Danish premier's response this time was surprisingly placatory: "We need very close cooperation with the Americans. The USA is our closest ally," Frederiksen said. According to her office, she has since had a lengthy phone call with the incoming US president about Greenland.

'We don't want to be Danes. We don't want to be Americans'
What are Trump's motives? Ulrik Pram Gad from the Danish Institute for International Studies in Copenhagen told DW that the president-elect's moves are in keeping with the so-called Monroe Doctrine that dates back to the 19th century: "The USA won't allow any hostile powers to have a foothold on the North American continent. So they want to be sure that no Chinese or Russians have installations in Greenland."

Frederiksen has repeatedly said that it is up to the Greenlanders to decide Greenland's future, and not Copenhagen.

The links between Denmark and Greenland have existed for hundreds of years. Greenland was a Danish colony until 1953 and is now a self-governing territory of the Kingdom of Denmark. Since 2009, the island has had the right to declare itself independent in a referendum. However, the island and its 57,000-strong population are heavily dependent on Danish state funds.

Greenland's Prime Minister Mute Egede is in favor of independence, but he does not want Greenland subsequently to become dependent on another state. "We don't want to be Danish. We don't want to be Americans. We want to be Greenlanders, of course," he once said in the presence of Frederiksen.

Ice-free shipping due to climate change
Greenland's resources are a major reason why it is of interest to other countries. For example, there is oil, gas and rare earths, which are necessary, among other things, for making electric cars and wind turbines. Currently, China almost has a global monopoly on these critical minerals.

Around 80% of the island is covered by a thick ice sheet, but the ice is retreating as a result of climate change, making the deposits more accessible. However, Greenland's government has blocked mining for environmental reasons up to now.

Rising temperatures and receding ice mean that ships can also navigate the waters around Greenland more easily, making the journey between Europe and Asia much shorter than through the Suez Canal.

What applies to merchant ships also applies to Russian warships and nuclear submarines. Both Russia and China are trying to expand their influence in the Arctic.

US troops stationed in Greenland
The United States has had a presence in Greenland for many decades. When Nazi Germany occupied Denmark in 1940, US troops landed in the then Danish colony to prevent a German invasion.

US President Harry Truman offered to buy Greenland for $100 million in gold back in 1946. Denmark refused, but a few years later agreed to a permanent American military presence, which became part of NATO's Cold War defense strategy.

The military base, now called Pituffik Space Base, has been greatly expanded and has an early warning system for missiles — as the shortest route from Europe to North America is via Greenland.

Why pay for what you already have?
Buying the island is less far-fetched than it might seem. There have been many similar examples in the past. In the 19th century, the US purchased Florida from Spain, Louisiana from France and Alaska from Russia. Denmark itself sold its part of the Virgin Islands in the Caribbean to the US for $25 million in 1917.

However, Greenland's prime minister has repeatedly rejected the idea: "Greenland is ours. We are not for sale and will never be for sale."

At the moment, however, Greenland cannot decide that on its own, says Ulrik Pram Gad. "Technically, if Greenland declares independence, they can do whatever they want with their independence," and join the USA, for example. However, he added that the idea of acquiring sovereignty and then selling it would seem ridiculous to Greenlanders.

He said that it was nevertheless conceivable that the US would offer to pay Greenland bigger subsidies than Denmark in exchange for security agreements. "But it's very difficult to envision Trump, the dealmaker, paying so much money for something he already has in the sense that since 1951 the US has an agreement with Denmark, co-signed in 2004 by Greenland, that the US basically has military sovereignty over Greenland."

Trump has already achieved something
If Trump's main aim was to get Denmark to pay more attention to security around Greenland, you might say he has already partially achieved his goal: Denmark has announced additional military spending of around €1.5 billion for the Arctic. Although this had already been planned, it was announced just hours after Trump's threat, which the Danish defense minister called an "irony of fate."

In addition, the surprisingly accommodating reaction of the Danish prime minister indicates that Denmark's government wants to avoid angering NATO's leading power.

Trump could also achieve something in Greenland itself. Ulrik Pram Gad says he could obtain a more explicit security guarantee that, in the event of independence, Greenland would never leave NATO or try to force the US to give up its military base there.

But the Danish political scientist suspects that the matter also reveals something about the future US president that goes beyond the Greenland issue: "That is the trouble we will all face during the next four years. Every time Donald Trump says something, all of us will run around like headless chickens trying to find out what is behind it. The thing is, maybe even he doesn't know."