When officials from the United States, Denmark and Greenland met last month in the Arctic island's capital, the session was reassuringly normal, with no discussion of a U.S. military or financial takeover of the Danish territory, multiple people familiar with the talks said.

That all changed less than two weeks later when Trump announced a special envoy to the vast island, Jeff Landry, who posted on social media that he would help "make Greenland part of the U.S." The appointment and the message stunned Copenhagen and blindsided senior U.S. officials across the administration who work on European and NATO issues, the sources said.

The exclusion of his own diplomats fit the pattern of Trump's foreign policy-making, which has veered wildly on a range of issues and has often been formulated without the national ?security officials who in other U.S. presidencies have helped steer policy.