President Trump’s idea of buying Greenland has evoked ridicule, mixed with the usual venom, in both Denmark and the United States. And Trump’s way of expressing himself has only increased the scorn: as he said on August 18, “Essentially, it’s a large real estate deal.” (If only Trump had said that buying Greenland would contribute, somehow, to combating climate change, then he would have had a respectful audience, no matter what his choice of words.)

Of course, it should go without saying that Democrats, joined by the Mainstream Media and the international tweeting class, will oppose anything Trump advocates for. And so in the short run, nothing is going to happen with Greenland.

Still, there’s a creeping realization that the dreaded Trump might be on to something. Hence this reluctant headline in Politico: “Trump’s Greenland Gambit Might Be Crazy—But It Could Also Be the Future.”

Moreover, undeniably, the “real estate” (a.k.a. geopolitics) of the Arctic region is in flux. That is, many players—including China and Russia, as well as the U.S. and multinational corporations—are seeking greater footprints in that area. To recall past geopolitical competitions in other parts of the world, we can say that a new Great Game, or maybe a Scramble, is at hand. This includes not only Greenland, but also all the area reaching to the North Pole.

Thus on August 23, the State Department announced plans to open up a consulate in Nuuk, the capital of semi-autonomous Greenland. We had opened a consulate there in 1940, prior to our involvement in World War II, and shrewdly taken custody of Greenland, as a way of keeping it out of Nazi Germany’s grip. To President Roosevelt, the thought that Hitler might be able to station bombers, U-boats—or even Wehrmacht soldiers—so close to North America was too terrible to contemplate.

During the war, Greenland was a strategic bridge to our allies, notably the United Kingdom and the Soviet Union; to this day, it’s a grave to many American airmen who died flying supply missions over its frozen vastness. We relinquished the earlier Nuuk consulate in 1953, even as we retained a military presence at Thule, north of the Arctic Circle, and elsewhere on that giant island.

As the State Department just wrote to the Senate Foreign Relations Committee, America has a “strategic interest in enhancing political, economic, and commercial relationships across the Arctic region.” The letter added that the consulate would serve as “a critical component of our efforts to increase U.S. presence in the Arctic and would serve as an effective platform to advance U.S. interests in Greenland.”

We might pause over those last words, advance U.S. interests in Greenland.

There we get a sense of motion, as in…Manifest Destiny. Admittedly, Manifest Destiny is not a PC phrase. Yet trendy pieties aside, it’s hard to argue with the long-term logic of national expansion as key to self-defense, as well as to greatness.

The phrase comes from the American journalist John O’Sullivan, writing back in 1845. O’Sullivan hailed “the right of our manifest destiny to overspread and to possess the whole of the continent which Providence has given us.” To the contemporary ear, all that sounds right-wing, yet in the context of the 19th century, O’Sullivan was a progressive modernizer. He stipulated that such expansion should be “for the development of the great experiment of liberty and federated self-government entrusted to us.”

Indeed, for reasons of realism as well as idealism, the U.S. was wise to follow O’Sullivan’s expansionary exhortations. After all, by the 19th century, as transportation and technology improved, vacant territory wasn’t staying vacant. That is, if we had chosen to leave, say, Oregon to the Chinook, Klamath, and Umpqua tribes, then some other great power would have moved in.

The most obvious alternative occupiers would have been the Russians, who had seized control of Alaska beginning in the 17th century. If we hadn’t bought them out in 1867, there’s every reason to think they would have continued to poke around the Pacific Northwest—unless, of course, the British in Canada drove them out. And the British, too, would have wanted Oregon—unless the Germans or Japanese had gotten there first.

Absent Uncle Sam, there’s no way to know who would have prevailed in that strategic welter; the only thing we can know is that the low-tech locals would have been overwhelmed by someone. Yes, might doesn’t make right, but superior technology surely does make for might.

Indeed, from an American point of view, it’s painful to think what the 20th century would have been like if the Russians, Germans, or Japanese had gained control of Oregon or any portion of the Pacific Coast.

Yes, of course there’s a limit to America’s reach. As we have discovered since the second half of the 20th century, the U.S. is ill-equipped to nation-build and democratize far-flung places that aren’t vital to our national interest, including Vietnam, Afghanistan, Iraq, and Libya.

Yet Greenland is closer, emptier, larger—and therefore potentially richer. Already, we know that it abounds with Rare Earth Elements; it’s a territory, after all, more than a quarter the size of the continental U.S.

So whether or not we ever buy it, we should seek more influence over its development. And that development will happen, of course, under someone’s flag—because both geopolitics and economics abhor a vacuum.

Indeed, as we ponder Greenland, we might think back to a classic work that persuaded geopoliticians across the world to think about territory in a more strategic manner. That was Alfred T. Mahan’s 1890 tome The Influence of Sea Power Upon History, 1660-1783. As Mahan, a U.S. naval officer, wrote, wise strategists need to think about location and logistics well in advance of any possible fighting:

In a sea war, as in all others, two things are from the first essential,—a suitable base upon the frontier, in this case the seaboard, from which the operations start, and an organized military force, in this case a fleet, of size and quality adequate to the proposed operations. If the war, as in the present instance, extends to distant parts of the globe, there will be needed in each of those distant regions secure ports for the shipping, to serve as secondary, or contingent, bases of the local war.

The lesson is clear: if trouble comes, a nation should always want a physical buffer, as well as forward bases. That’s why we already have that base at Thule, and why, if the Arctic keeps warming—potentially turning the mostly frozen Arctic Ocean into navigable blue water—we’ll want even more of a presence in that new seafaring zone.

Mahan was also keenly attuned to the issue of resources: as he wrote, a nation must think about “cutting off the resources of the enemy while maintaining its own.” In the 130 years since, sea power, of course, has been layered by air power—and now air power is layered by space power. Yet on any physical plane, the principle of maintaining mastery of resources, and resource routes, has remained vital.

Of course, some will protest that such machtpolitik thinking is simply wrong, even if other countries are doing it. And yes, such passivity is the attitude of the European Union, which seems content to watch the larger world go by while maintaining its pristine self-image. (Although even the EU has been active on the issue of Brazil’s burning Amazon forests—a reminder that everyone has at least a transnational preoccupation or two.)

In the meantime, in the larger world, territory and resources—from Jerusalem to the South China Sea to Crimea to Kashmir—have been divvied up in new ways, and new forms of power have emerged.

Now there’s the looming question of the fate of Greenland, which is some darn fine real estate.