How has Trump changed world order in 100 days? Donald Trump represents a departure from the America we've known since 1917, our security and defence analyst Michael Clarke has said. He described America's influence on the world stage as "fundamental" for decades, but pointed out that perception had now changed under Trump. Clarke explained there were four big powers in the world at the moment; America, China, Russia and India, and they "make the political weather the rest of us have to exist in". But he said three of those four are now revisionist because they want to change the rules of world politics. Clarke said Trump has proven to be a revisionist himself, adding "that means we in Europe are in for a very bumpy ride in the next decade, maybe more". "We've relied on that American-influenced world of the 20th century... that's gone, it's gone really quickly," he said. Clarke also explained that uncertainty is one thing Trump now can't escape from, saying "even if US policy changed tomorrow, what they can't now avoid is the fact that nobody trusts America to be consistent". Watch Clarke's full analysis here: