Though the president-elect's rhetoric is unusual, for over a century a succession of US presidents have tried to gain control of Greenland.

The president-elect said the United States needed the island, which is a semiautonomous part of Denmark, for national security reasons. But there are other possible interests.

President-elect Donald Trump’s attention returned Tuesday to an idea that has fascinated him for years: acquiring Greenland for the United States. In a news conference Tuesday, he refused to rule out using military or economic force to take the territory...