One of the most remarkable aspects of the Trump presidencies is how he makes so much obscure law return to the fore. It has been well documented how much of the Constitution Trump has implicated. Indeed, one could write an entire book about Trump and the Constitution. (I plan to write a trilogy on the topic.) But Trump also affects other aspects of the law.

The latest instance comes in comments Trump made about Greenland. Trump said:

"The fact that they [Denmark] had a boat land there 500 years ago doesn't mean that they own the land."

Of course, Trump is referring to the doctrine of acquisition by discovery. Chief Justice Marshall discussed this doctrine at length in Johnson v. McIntosh. Most 1Ls read this case in property. In this canonical decision, Marshall explained that European explorers "acquired" land in the Americas pursuant to the discovery doctrine. The discovery doctrine is the root of most property ownership of the United States. For whatever it is worth, the Vatican repudiated the discovery doctrine.

I'll admit I know little about the history to Greenland. I found an article (fittingly) titled "The Rediscovery of Greenland during the Reign of Christian IV." During the thirteenth and fourteenth centuries, there were Nordic settlements in Greenland. However, those settlements faded away by the early fifteenth century. Starting in 1605, the Danish king sent expeditions to Greenland. (This is likely the 500-year-old boat that Trump is talking about.) Danish claims to Greenland trace to this re-discovery.

Even as Trump rejects Denmark's claim to the land by virtue of the discovery doctrine, at same he asserted that the United States could acquire Greenland by conquest.

So far, Trump has not had much effect on my Property Law class, but that has now changed.