Donald Trump’s signature thought on political economy–mercantilism–had its heyday in the 17th and 18th centuries, when the European powers disposed of property without taking the slightest interest in the wishes of the indigenous people. He also wants to “take the oil” in Iraq, Syria, and Venezuela. It should come as no surprise, therefore, that he wants to buy Greenland. It’s completely consistent with his view of the world.
He probably thinks of Alaska as a precedent, but that was 150 years ago, and the Tsar didn’t exercise any control over Alaska outside of a few fairly miserable settlements on the sea. Times have changed a bit since then.
We probably should be grateful that he didn’t just invade, instead.