Brent Molnar, in his Voice of Reason newsletter (Substack, alas):

If the United States follows through on the threat to invade Greenland, we need to be crystal clear about what happens the next morning. This is not a real estate transaction or a routine military exercise. It is the geopolitical equivalent of pulling the pin on a grenade in a crowded elevator. The moment American boots hit the ground in Nuuk to seize territory from a fellow NATO member, the world as we know it ends. The consequences will not be temporary sanctions or angry letters. They will be total, permanent, and devastating.

The fall of NATO, “the closure of every U.S. military base on the continent,” Europe dumping their dollar reserves (“sending the value of our currency into a death spiral”), U.S. companies expelled from European markets (“Trillions of dollars in market capitalization will be incinerated in minutes”), U.S. airlines banned from European airspace, the end of visa-free travel to (and legal protections in) Europe.

This is the end of trust, and it does not reset. You cannot invade a democratic ally and then say “my bad” four years later.

The biggest benefit of international cooperation isn’t the loud wars they prevent but the quiet stability they provide.