Trump doesn't want this. He didn't come up with the idea.
Trump was told and encouraged to want this by the little birdies at the DoD.
Trump absolutely drives this. You're deluded if you think this whole thing comes from the DOD. He is in effect a king at this point and he rules by posting in social media.
What do you expect (e.g.) Norway to do except disentangle, when their PM sends this text and gets back this response? And note that Finland's president (Alex there) has been one of the big proponents of continuing to engage with Trump. So, honest question, what should Finland, Norway, etc, do?
https://archive.ph/rjEtm