Living in a G-zero world

Donald Trump's decision last week to remove the US from the Paris Agreement on climate sent a crystal-clear signal that we're now living in a G-zero world, a world without consistent leadership. Who is leader of the free world today? Not Trump, the first US president since the 1930s who does not believe that international leadership is in the US national interest. For Trump, everything is a transaction. He sees the world not as a community - sometimes cooperative, sometimes contentious - but as an arena in which strong leaders fight for dominance. This view appeals to Trump personally, and he knows his loyal supporters like it too.

Are Europeans now leading the free world? Not exactly. The transatlantic alliance has been gradually hollowing out for many years, and the election of Trump has veteran leaders like Germany's Angela Merkel and new ones like France's Emmanuel...