Opinion | Trump’s Greenland Plan Shows He Has No Idea How American Power Works

The result is that most American citizens have only the vaguest sense of the extent and character of the security system that makes their country so powerful. It seems Mr. Trump can be counted among them. “Strategically, it’s interesting,” he has said, concluding that the United States should therefore buy it.

What he misses is the fact that, strategically, the United States already has use of Greenland. After failing to acquire the territory in 1946, Washington cut a deal with Denmark that allowed it to operate bases in Greenland, the most important of which was Thule Air Base on the northwest coast. Over the objection of the Danish government, the United States military stored nuclear weapons in Greenland and flew nuclear-armed B-52’s over the country — part of a secret airborne alert program targeting the Soviet Union. Stanley Kubrick’s 1963 film “Dr. Strangelove,” filmed partly over Greenland, depicts this program.

In 1968, a B-52 flying near Thule with four Mark 28 hydrogen bombs crashed, hitting the ice at more than 500 miles per hour. The bombs didn’t detonate, but they spread radioactive debris for miles. From Greenland’s perspective, this was a hair-raising disaster, but from Washington’s it showed the benefits of foreign bases. The Air Force could make dangerous flights over Greenland with impunity.

Greenland also has strategic value as a source of raw materials. But here, too, the fact of its being foreign is no impediment. Denmark is a member of NATO and Greenland in 2013 lifted a ban on mining radioactive materials; nothing stands in the way of the United States purchasing what it needs. “We’re open for business,” Greenland’s foreign affairs ministry reassured Mr. Trump, in response to his talk of annexing the territory. That is true; Greenland and Denmark are so closely tied to the United States in both trade and defense that it is hard to imagine the relationship being severed.

The cost of secure trade and bases, however, is collaboration with foreigners, an activity the president does not relish. He has threatened to pull the United States out of so many treaties and trade agreements that it is easy to lose count. Though Mr. Trump celebrates American military might with parades and tanks, his 2017 budget proposed closing bases, and he has called to bring troops home from host countries that, in his view, pay too little. Mr. Trump wants power over the world, not presence in it.