Donald Trump has warned the US may pull out of NATO if America's allies don't agree to its acquisition of Greenland. 'Will you pull out of NATO if it doesn't help you acquire Greenland,' a reporter asked the president outside the White House on Friday. Trump warned: 'We're going to see. NATO has been dealing with us on Greenland, we need Greenland for national security very badly. If we don't have it we have a very big hole in terms of national security, especially in terms of the Golden Dome.' The Golden Dome is a proposed multi-layer missile defense system...