Trump is hailing his new deal with Greenland and Denmark - but a deal already existed. So what changed?

The president then wrote that he had "permanently and conclusively addressed this very important situation." On Tuesday, a new security agreement between the U.S., Denmark and Greenland was officially signed at the UN General Assembly in New York.

However, the U.S. already had a security arrangement with Denmark and Greenland dating back 75 years. So what, if anything, has changed?

"If we try to look at the new defence agreement compared to the old defence agreement, I would characterize it as a moderate improvement for the U.S.," Mikkel Runge Olesen, a senior researcher at the Danish Institute of International Studies, told CBC News.

"But it's a moderate improvement that has come at an immense cost."

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