Having won more votes than any presidential candidate in American history, Joe Biden might have hoped for a triumphant entry into Washington. Instead, he travelled to the inauguration in a private plane to deliver his speech to more members of the National Guard than guests. A combination of the pandemic and security fears ruined normal proceedings: the event had become a target, crowds too great a risk. The emptiness embodies the problem Biden needs to overcome: not just the spats between left- and right-wing politicians, but the unravelling of trust in American politics. His challenge goes beyond governing. It is the question of how to unite the country — or, at least, how to repair the social fabric so that the scenes of the past few months are remembered as a freak incident in US history, rather than the start of a new, dangerous era.