The time for flattering Donald Trump is over, and Europe should hit back hard economically if the ‍US imposes tariffs on NATO allies that sent troops to Greenland, ex-NATO boss and former Danish Prime Minister Anders Fogh Rasmussen said on Tuesday. Rasmussen said Trump’s insistence that Greenland – a semi-autonomous Danish territory – should become part of the United States represented the biggest challenge to NATO since its establishment in 1949.For all the latest headlines, follow our Google News channel online or via the app.“It’s really the ⁠future of NATO that is at stake,” said Rasmussen, who offers a unique perspective on the crisis as a former leader of both Denmark – from 2001 to 2009 – and NATO, where he served as secretary general from 2009 to 2014.“The time for flattering is over. It doesn’t work. The fact is Trump only respects force and strength. And unity. That’s exactly what Europe should demonstrate right now,” he told Reuters from the World Economic Forum