Trump could take Greenland more easily than Putin took Crimea - 5 helicopters might be enough - and who would sanction him?

I turned to Politico, a magazine I can't stand usually, to see how the European political elite is coping with the US threat to Denmark's possession Greenland. 

A Politico journalist has spoken to a Danish politician who asked for anonymity to speak freely.

“It could be like five helicopters ... he wouldn't need a lot of troops. There would be nothing they could do.”

If Greenland can be annexed because the USA needs her "very badly" and Denmark doesn't then populous China should be allowed to annex empty Asian Russia.