Tom Cotton: Send In the Troops

This week, rioters have plunged many American cities into anarchy, recalling the widespread violence of the 1960s.

New York City suffered the worst of the riots Monday night, as Mayor Bill de Blasio stood by while Midtown Manhattan descended into lawlessness. Bands of looters roved the streets, smashing and emptying hundreds of businesses. Some even drove exotic cars; the riots were carnivals for the thrill-seeking rich as well as other criminal elements.

Outnumbered police officers, encumbered by feckless politicians, bore the brunt of the violence. In New York State, rioters...