FWIW the path of much less resistance seems to be financial (as usual). The public rhetoric on both sides is probably just kayfabe while they negotiate the final price.
https://www.wsj.com/politics/national-security/rubio-tells-lawmakers-trump-aims-to-buy-greenland-downplays-military-action-5c94e05c
https://www.wsj.com/politics/national-security/rubio-tells-lawmakers-trump-aims-to-buy-greenland-downplays-military-action-5c94e05c