CHARLES LIPSON: This is not what a constitutional republic looks like. “The scale and symbolic significance of this attack are new and profoundly troubling. But it is also the culmination of several disturbing trends. For months now, we have witnessed a degradation of public order — mobs roaming city streets, unpunished; an effort to take over and firebomb a federal courthouse in Portland, unpunished; delegates attacked on the streets of Washington after the Republican convention, unpunished. And now this, far worse than anything that came before.”