WASHINGTON -- Greenland's geography, sitting on the mouth of the Arctic, puts it at the doorstep of a potential future battleground with Russia and China, and the U.S. will defend it if Denmark will not, U.S. President-elect Donald Trump's former national security adviser said on Sunday.
Appearing on Fox News, Robert O'Brien explained that Trump's interest in the world's largest island is related to the future of maritime transportation.
