Storming of the Capitol

As Aristotle observed in the Poetics, the end of a drama should be surprising yet inevitable. If that is true, then Donald Trump's four years as President of the United States have just drawn to a fitting conclusion.

The Capitol is the most imposing building in Washington, D.C. When tourists first arrive in the city, they often mistake it for the White House because it looms so large. And though American democracy has experienced many turbulent days, the country's Congressmen and Senators have safely been able to go about their business in its august halls for over two centuries. The last time the enemies of democracy managed to storm the Capitol was in 1814, when British troops marched through the streets of Washington.

This helps to explain why Wednesday's events will, unlike so many other sordid tales of the past four years, be remembered for decades. For the first...