For all their pomp, most multilateral summit meetings 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.

Still, there has never been a disaster like the G7 meeting that just took place. It could herald the beginning of a trade war, maybe even the collapse of the Western alliance. At the very least it will damage America’s reputation as a reliable ally for decades to come; even if Trump eventually departs the scene in disgrace, the fact that someone like him could come to power in the first place will always be in the back of everyone’s mind.

What went down in Quebec? I’m already seeing headlines to the effect that Trump took a belligerent “America first” position, demanding big concessions from our allies, which would have been bad. But the reality was much worse.