Wherever in the world it may happen, the storming of a government building by an angry mob often results in the same, familiar scenes. Security services, overwhelmed or unwilling to use force, have to make way for rioters who proceed to parade through the offices, gawk at the furnishings in the corridors of power and send legislators scurrying for safety. The atmosphere among the intruders is jubilant – they feel justified in openly disrespecting a political class that they believe has disrespected them – but also menacing, as though the national order itself is under threat.
These scenes played out in Washington on Wednesday, when hundreds of supporters of US President Donald Trump, including many who were armed, overran the Capitol, America's legislative assembly building, while the Senate was in session to confirm the election of his successor, Joe Biden.
But what happened in Washington was not an attack on the political class. Encouraged by the President himself as well as several of his political allies in order to impede the peaceful transition of power, it was an attack on the institutions fundamental to America's democratic political system. It was the attempted subjugation of good government to mob rule by an extremist fringe.
Yesterday's events demonstrated that courts and elections alone are not enough to safeguard American democracy. Stability and progress depend on the responsible stewardship of leaders, who can uphold a sense of reverence for institutions even when they produce a result contrary to their wishes.
Seemingly unprepared for the incursion on the Capitol, building security and Washington police were quickly overcome. The ineffectiveness of law enforcement was galling to many; a largely peaceful assembly in Washington led by activists from the Black Lives Matter movement in June was met with an immense show of force. This time, the federal government opted not to deploy the National Guard, a reserve branch of the military, to restore order until long after politicians in the building were forced to evacuate and many of the legislative offices had been vandalised. Whatever subjective morality drives the mob to invade such hallowed institutional walls, once they are breached, some of the reverence is lost for good.
As the rioters continued their occupation of the building, Mr Biden addressed the nation, calling the events "an assault on the citadel of liberty". His remarks evoked the longstanding self-image of America as a "city on a hill", an elevated fortress from which to defend a certain set of values while projecting them elsewhere in the world, either actively or by example.
Whatever foreign policy Mr Biden's incoming administration chooses to adopt over the next four years, its priority will necessarily be to project, in its affairs at home, America's example. People around the world watched Wednesday's scene at the Capitol less with respect than with disbelief, alarm and even ridicule.
Mr Biden's chief task after his inauguration on January 20 will be to unite a country shaken by deep divisions. This will be a delicate and arduous mission that involves, in part, seeking accountability for these displays of violence without escalating tensions further on either side. If he can manage it, America may see its citadel restored.