President Trump’s idea of buying Greenland from Denmark probably has a slimmer chance of happening than hitting an iceberg at the equator. But the suggestion shows constructive, creative thinking, and it’s an intriguing idea.

At 836,330 square miles, Greenland is almost precisely the size of Alaska and California put together. It is rich in coal, zinc, copper, and iron ore. Perhaps even more important, it could have significant strategic military value by providing bases in the North Atlantic and particularly in the Arctic, where Russia repeatedly makes territorial claims (including to the North Pole itself) that are spurious but provocative and potentially destabilizing.

Granted, the United States already has a key military installation there, the Thule Air Base, which (to quote the Wall Street Journal) “includes a radar station that is part of a U.S. ballistic missile early-warning system. The base is also used by the U.S. Air Force Space Command and the North American Aerospace Defense Command.”

There seems no danger of Denmark abrogating the treaty that gives the U.S. the right to operate Thule. But still, ownership makes things permanent, and of course it would allow the U.S. to create other bases in Greenland if needed.

The U.S. has intermittently expressed an interest in buying Greenland since 1867, and in 1946, President Harry Truman actually offered to purchase it for $100 million (the equivalent of $1.316 billion today).

While there is absolutely no sign that Denmark or the mostly autonomous Greenlanders themselves would be interested in becoming part of the U.S., it does make a certain sense for them. Greenland holds no military value for a nation as small as Denmark, which has no need to worry itself with “force projection” the way the U.S. does. And while the natural resources could be as valuable to Denmark as they would be to the U.S., Denmark right now spends nearly $600 million annually in subsidies to Greenland’s government. Ridding itself of those costs, plus getting a big lump-sump payment from its American allies to boot, could be a good deal for the Danes.

Each major time the U.S. has bought territory — the Louisiana Purchase in 1803, Alaska in 1867, what are now the U.S. Virgin Islands in 1917 — has proved to be a good investment. This one might be just as wise.

The price would need to be negotiated. The wishes of Greenland’s current population should be considered. The structure of territorial governance would need to be worked out. These and other considerations might argue against the deal even if Denmark were willing to sell.

In sum, further consideration might show the purchase isn’t practical. We won’t know, though, until we explore and analyze the possibility. It is very much to Trump’s credit that he has an open mind about such a thing. Long-term American strategic interests could well benefit, so it certainly doesn’t hurt to take Truman’s idea off the ice and see if it will float.