Check the record. Among the most recent American officials to advocate the taking of Greenland was, well, Secretary of State William Seward. In the second half of the 1860s!
This statesman of “Seward”s Icebox” fame feared England would take control of Greenland, thereby further thwarting the plans of his “manifest destiny” crowd to annex Canada.
Some eight decades later, there was also the original cold war monger, Secretary of State James Byrnes, who offered Denmark $100 million for Greenland—the better to keep the Ruuskies off of the icebergs. Instead, Washington eventually settled for a rent-a-base at Thule, Greenland that actually made sense as a radar warning station at the time, and which we remember quite well.
To wit, during 1954-1957 the US set up a chain of radar stations called the DEW Line, stretching from Alaska across northern Canada to Greenland, providing systematic capacity for long-range detection of incoming Soviet bombers. It was a key part of the continental defense network integrated into NORAD and we were mightily impressed when we read all about it in our Weekly Reader as a 4th grader in 1955.
Since he is now our same age at 79 years, the Donald undoubtedly read about the DEW Line in his Weekly Reader, too. But apparently he never got over the wonder of it.
After all, back then the maximum cruising speed of the Soviet Tupolev TU-16 was about 500 mph. So if any attacking Soviet bombers were detected by the radar station at Thule they were still 5 hours and 15 minutes from Washington DC, which is about 2,600 miles away. The US strategic command thus had plenty of time to scramble an extensive fleet of Air Force fighters and interceptors to bring the Soviet bombers down long before reaching targets in the USA.
No more. Today’s Russian hypersonic Oreshnik missiles can easily travel at peak speeds of mach 10 and average speeds of mach 5 or about 4,000 miles/per hour. This means that they could get from Thule to the nation’s capital in barely 40 minutes.
But even then the 40 minutes of “warning” time from Greenland-based radar isn’t what it might appear to be. That’s because there is no existing or even conceptually likely defense system against hypersonic missiles that would effectively protect American military and civilian targets—especially if these hypersonic missiles were camouflaged with swarms of decoys. In effect, warning time is irrelevant because effective anti-hypersonic missile defensive counter-measures are nonexistent.
Besides, even today’s 40 minutes by hypersonic missile from Greenland to the White House isn’t all that. It’s actually about 10 minutes.
That’s because in the case of a totally implausible Russian first strike (see below), the latter would be led by a hypersonic missile attack on Thule, which is exactly 10 minutes from Russia’s Olenegorsk Air Base on the Kola Peninsula. Of course, the Thule base has no reliable anti-missile defense, in any event, and would therefore be obliterated before they even got the President out of bed in the White House.
That is to say, in today’s world there is no meaningful warning time for traditional defensive measures to protect the airbase at Thule. It’s essentially a sitting duck aircraft carrier on an iceberg, equivalent to Washington’s equally worthless $40 billion carrier battle groups, which also sit out on the blue waters waiting to be obliterated by a hypersonic missile attack.