The lessons from last summer’s insurrection are clear to sober-minded observers. When leaders indulge the mob, they embolden the mob. The best way to maintain or restore order is an overwhelming display of force, which often can prevent the use of force.

Too few of our leaders learned these lessons. The president heedlessly goaded the crowd on the mall, while some Republicans had spent a week encouraging false hope that Congress could overturn the results of the election. Washington’s left-wing mayor, Muriel Bowser, insisted National Guardsmen come unarmed to the protest. Guardsmen would have to return to their armory to retrieve weapons if things spiraled out of control, which they did. The mob outnumbered and overwhelmed Capitol Police and Secret Service at the Capitol, despite their commendable efforts to maintain control.

Some liberals appear to have shed their reservations about the use of force now that the mob carries different signs and chants different slogans. Some of the same pundits who called roughly half the country “fascists” last year for thinking troops may be necessary to restore order now ask where the troops were on Wednesday. Perhaps they’ve learned the lesson that political violence leads to more political violence. If the lesson doesn’t stick, they’ll soon learn another: Revolutions tend to eat their own.

Mob rule contributes to a more general breakdown of public order.