The shooting of a young black man by a white police officer in Ferguson, Mo., has focused the nation’s attention on the continuing mistrust and division between urban police departments and the black communities they serve. Part of the tension was created by the initial response of police to protests. Police in riot gear, carrying military style weapons, were accused of overreacting. The so-called “militarization” of police departments has been called into question.

After the September 11 terror attacks on the U.S., the federal government decided to make surplus military weapons and equipment available to police departments for use in case of emergencies. Now, many people are arguing that most police departments will never confront that kind of terror attack, and they don’t need the arsenals of automatic weapons.

But terrorists aren’t the only threat out there. Criminal gangs, drug dealers and other bad sorts have increasingly been armed with automatic weapons and assault rifles. It doesn’t make sense to ask police officers to take them on without being at least as well armed as the criminals.

How and when police departments use the riot gear may be a subject for debate, but as long as criminals are carrying assault weapons, so should police.