President Trump had a “firm” phone conversation with Denmark’s prime minister last week to convey his serious intentions of acquiring Greenland, according to a report citing officials privy to the talk. Trump has been aggressive in his desire to make Greenland a US territory to bolster national security in the Arctic region — and has even refused to rule out using “military force” to get it. The Danish government, which has ownership of the largest island in the world, has said Greenland is not for sale and will not be a part of the US. Trump’s conversation with Danish PM...