Canada and Denmark have fought a brutal territorial war for over 50 years. [View all]

And by brutal I mean they took turns planting their flag and leaving a bottle of booze for the other guys.

It was only resolved in 2022.

They could have used a seasoned diplomat like Trump to settle this years ago.

from wiki:

The Whisky War, also known as the Liquor Wars,[1] was a bloodless war and border dispute between the Kingdom of Denmark and Canada over Hans Island. Between 1973 and 2022, the island was under dispute between the two nations, although never amounting to direct conflict or violence.

In 1984, Canadian soldiers visited the island and planted a Canadian flag, also leaving a bottle of Canadian whisky.[10] The Danish Minister of Greenland Affairs came to the island himself later the same year with the Danish flag, a bottle of Schnapps, and a letter stating "Welcome to the Danish Island" (Velkommen til den danske ø).[11][12][13] The two countries proceeded to take turns planting their flags on the island and exchanging alcoholic beverages.[14] In 2005 a Canadian man and an unknown source on the Danish side also posted advertisements on Google to "promote their claims".[14][15][16]

The minor border dispute was often considered humorous between the two nations, with diplomats displaying good humour. Despite the serious official nature of the matter, the manner in which the conflict was prosecuted was light-hearted, demonstrated by the length of time taken to settle the dispute, if nothing else. Both nations are on friendly terms, and are also founding members of NATO.

https://en.wikipedia.org/wiki/Whisky_War