Donald Trump has made it clear that he likes the idea of Greenland seceding from Denmark. “For purposes of National Security and Freedom throughout the World, the United States of America feels that the ownership and control of Greenland is an absolute necessity,” Trump said in a post on Truth Social.

Of course, the road to a US annexation of Greenland could go at least two different ways. One way is outright unilateral annexation in which the US declares the island to be US territory. That’s essentially what the US did in places like the Philippines in the wake of the Spanish-American War.

The obvious problem with this method is that the United States likes to claim that it is the great moral nation that adheres to a “rules based order.” To simply annex Greenland without an internationally recognized referendum, voted on by Greenlanders, would look a lot like, say, the Russian occupation of South Ossetia.

On the other hand, US annexation would be a lot easier to justify if Greenland voters formally secede from the so-called “Danish Realm,” the loose-knit polity that includes Denmark, Greenland, and the Faroe Islands. If secession wins a majority vote, this would be a crucial first step in paving the way for either de jure or de facto annexation.

If Greenland does vote to secede from Denmark, it won’t be the first time that a Danish overseas territory has voted to do so. This time around, though, it is likely the US will be at the center of the pro-secession effort.