Germany, along with several other European allies, reportedly had informal discussions about what NATO troops would do if the US president carried out his threats, according to diplomatic sources quoted by The Telegraph. There were even concerns about whether Article 5, the mutual defense clause of NATO, could be triggered if the US were to invade another NATO member country.

After Trump began his second term in the White House, he openly considered taking Greenland, an autonomous part of Denmark, by force. The US president said that if Copenhagen refused to give up the Arctic island, it would be an "unfriendly act," especially with Russia and China increasing their presence in the region. Berlin's involvement in secret talks drew criticism from some strong supporters of Ukraine in NATO, particularly because German Chancellor Olaf Scholz has refused to send troops to Ukraine. “Berlin doesn’t want to send troops to Ukraine because the situation is ‘too ambiguous’ but is openly flying kites about sending NATO troops to Greenland,” a NATO diplomat told The Telegraph. “It’s a moral compass without a needle.”

According to Austrian General Robert Brieger, who leads the EU military committee, it would send a "strong signal" to send troops commanded by Brussels to Greenland. European countries are at odds on how to respond to Trump's comments without sparking a transatlantic crisis. Speaking in English to "whom it may concern," Scholz has been Europe's most outspoken critic of Trump over Greenland, stating that "borders must not be moved by force" as an international principle. 

Danish Prime Minister Mette Frederiksen has advised allies not to react to the U.S. president to prevent increasing tensions. She supports U.S. security concerns about the Arctic and has committed to strengthening Denmark’s military presence in Greenland but made it clear that the island is not for sale. She has started a European tour to gain the support of NATO allies and EU members in private. She will stop at Downing Street to speak with Sir Keir Starmer.