Occupying Greenland and the Canadian arctic was almost entirely about detecting bombers coming over the pole. Subs and ICBMs made those bases useless. But Trump could literally think it's 1965.

To believe that man has any intentions behind is actions is wild. He's easier to steer than a toddler with sugar treats. Someone told him to do it, everyone else complained, he tripled down to own the libs. He has no long term plans there, someone else might, but unless you can tell me who...we cant really assume assumptions. My guess is Putin told him to do the Greenland thing to destabilize nato

Nah, it seems much more likely to me that he's all about the resources there and making money from them, as well as controlling the and projecting power from the entire hemisphere around US soil.

Ballistic missile defense may have been something he heard from someone, but I seriously doubt he makes strategic considerations and decisions like that, at least as a or the primary aspect.