It’s one thing to say an area like Greenland has minerals; it’s another thing to be able to extract those minerals at an acceptable cost. From Doug Casey at internationalman.com:

International Man: President Trump has openly voiced his interest in having the US government take control of the Panama Canal.
He has even suggested that he wouldn’t rule out using military force to make it happen.
What is going on here?
Doug Casey: Panama, like most countries, is an artificial construct; it’s not part of the cosmic firmament. It came into being when it seceded from Colombia in 1903, midwifed by US intervention. That was a “good” secession, unlike that of the Donbas from the Ukraine in 2014 or the South from the Union in 1861, which everyone knows were “bad” secessions.
The US then bought the Zone (5 miles on either side of the proposed canal) from Panama for $10 million, which was 500,000 ounces of gold. That impresses me as a fair price, considering it was an undeveloped fever-ridden jungle at the time and that gold is worth nearly $1.5 billion today. Another $40 million (2,000,000 ounces) was paid to buy out the previous French developer. In those days the US still—sometimes—dealt with a measure of honor and propriety. Then, another $350 million (17.5 million ounces) was spent to build the canal itself.
It makes sense to think in terms of gold since that was money then. It was the largest US investment in history up to that time. Be that as it may, creating Panama enabled the US to build the canal—to the great advantage of all concerned.
Anyway, the canal now supposedly yields $3 billion (+/- 1,000,000 ounces) of profit on about $5 billion of gross receipts per year. It’s not a giant money machine in today’s context.
Panama has been de facto US territory and the Canal Zone de jure US territory, fair and square, from the get-go. Until Jimmy Carter “sold” the Zone to Panama in 1977 (for a token $1) because he felt it was the right thing to do. I disagree, but everybody’s got an opinion. Since then, the Panamanians have run the canal competently and greatly improved it.
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