The deadly riot at the US Capitol bore the markings of an organized operation planned well in advance of the January 6 joint session of Congress. A small number of cadre used the cover of a huge rally to stage its attack. Before it began, I saw from my vantage point on the West Front of the Capitol, what appeared to be four separate cells or units: Plainclothes militants. Militant, aggressive men in Trump and MAGA gear at a front police line at the base of the temporary presidential inaugural platform; Agents-provocateurs. Scattered groups of men exhorting the marchers to...