Maybe Trump was acting out and inventing vast evils because he couldn't stand having to spend hours with powerful people who will neither flatter nor bribe him. For all their pomp, most multilateral summits are boring and of little consequence. I once spoke to a state department official who had a role in putting these meetings together; he described his job as "policing the nuances", which gives you an idea about how much is normally at stake.

Occasionally, however, such meetings do have real consequences, good or bad. The 2009 G20 summit, at which nations agreed to provide economic stimulus and loans to troubled countries in the face of the financial crisis, played at least some role in helping the world avoid a full replay of the 1930s. The 2010 summit, by contrast, effectively endorsed a turn to austerity that significantly delayed recovery and, arguably, partially set the stage for the rise of political extremism.