Trump threatens to abandon even the impression of a collective approach to projecting US power through stable alliances and joint institutions. His sudden decision to attack Iran is of course the main case in point. With the collapse of Russian power, its European leaders had to try to prove its continued relevance. As US concerns tilted away from Europe, Nato had to show that it had ‘out of area’ capabilities. As he pursues his attack on Iran, Trump’s talk of being the peace president looks more and more ridiculous.