President Donald Trump managed to spend two days in the company of world leaders he has long antagonized without any visible eruptions.

There were no feuds, or at least none publicly detected, as Air Force One took off from Buenos Aires on Saturday night. Trump signed on to a statement of principles with the other leaders at the Group of 20 summit, the kind of document he refused to endorse at a summit in Canada a few months earlier. He curtailed his ambitions by canceling his meeting with Putin, and made nice with the European leader he most regularly trashes, German Chancellor Angela Merkel.

Trump's self-restraint continued as he answered a few questions from reporters. When one asked whether he had any regrets about his past criticisms of Bush and his family, Trump paused for a moment and then decided not to engage.

The G-20 is a multilateral organization, but Trump and some of his advisers are hostile to the concept of group decision-making. So Trump's assent to the joint statement of G-20 leaders reflected a compromise. The document reiterates a shared commitment to a "rules-based international order" and global trade, but includes a critique of the World Trade Organization, a body Trump rails against.

Thomas Wright, a senior fellow at the Brookings Institution, said, "The worry was that things could unravel, so there was a retraction of ambition from the other democratic leaders. They are worried about him creating a fuss over attempts to forge cooperation, which means these summits now are just gatherings of the leaders without a real agenda. That's the function of Trump."