US President Donald Trump has left NATO leaders reeling after his uncompromising statements about their refusal to meet their financial commitments to the Alliance and their trust to American military investment to do the hefting to protect the continent. It was an extraordinary spectacle to see EU leaders standing in a line while Trump lambasted them collectively. In the end a few of them snickered to each other when the president appeared to demonstrate a loose grasp on some of his facts. However their embarrassment was clear. Trump was stepping outside the bounds of normal diplomatic language. It is always assumed that politicians sometimes row and yell at each behind closed doors. But once out in the public gaze, at worst they hint at disagreements in statements that are generally packed with redundant verbiage. Not for Trump. He gave his fellow NATO leaders both barrels. The result is that German Chancellor Angela Merkel has already said that Europe can no longer rely on the United States and should take its destiny in its own hands. This was not the outcome that Trump may have wanted. But unlike his successful visit last week here in the Kingdom, the president left some ruffled feathers in Europe. The way he elbowed aside the premier of Montenegro to put himself in the front row for a photo-call was caught by the world's media. The posture he then struck was compared to that of the Italian dictator Benito Mussolini. Then there were the handshakes, particularly that with France's new president, Emmanuel Macron. Trump appeared to wrench the Frenchman's arm almost out of its socket then squeeze the hand really hard. However Macron got his own back with a later handshake when he himself gripped Trump's hand so forcefully, footage showed it turning white. The American straightened his fingers and pulled them away, so uncomfortable was the grasp. This apparently petty stuff unfortunately points to more serious differences that have clearly arisen between the suave and cultured European leaders and the no-nonsense and not obviously cultivated Trump. This is a pity and it is dangerous. American voters chose Trump because they were fed up with the liberal establishment's blithe and elitist determination to do what it considered right regardless of the concerns of ordinary people. Trump's rejection of man-made climate change is actually also a rejection of the Green agenda, which at its most extreme considers humankind to be a cancer destroying the world and has called for radical reductions in population, without specifying how. There is a strong argument that the climate science has become politicized and that consensus among scientists somehow validates policies, which are still based on tenuous research. Trump, however, has not made the anti-Green case that the world has survived major warming and cooling cycles before. The international community needs to be challenged. No idea is so absolutely good that it cannot benefit from being debated further. Here then perhaps is a case of the right message but the wrong person delivering it. Ever since he won the White House Trump has been the target of unprecedented personal abuse by an aggrieved liberal establishment. America's EU allies ought to be thinking about what Trump says instead of sticking their fingers in their ears and singing "La-la-la-la" and sneering and mocking the leader of the free world as gauche, unsophisticated and ill informed.