President-elect Donald Trump still wants to buy Greenland, having previously likened it to a giant real estate deal. If so, he seems to have forgotten one relevant precept: Why own when you can more profitably rent?

When the U.S. bought its way into the Arctic by purchasing Alaska from Russia in 1867, it also contemplated making a bid for Greenland, which is geographically part of North America but constitutionally part of Denmark. The U.S. also offered Denmark $100 million for Greenland after World War II. Instead, Washington got a defense treaty centered on Thule Air Base, now Pituffik Space Base, the U.S. military’s most northerly installation on Earth and strategically critical since the early years of the Cold War.

Greenland, granted self-rule in 2009, remains of vital interest to the U.S. Roughly as large as Alaska and Texas combined, it sits astride strategic sea lanes like the Northwest Passage and the Greenland-Iceland-U.K. gap, as well as beneath Arctic flight paths (including those for missiles).