Baltimore isn't the only U.S. city that has seen a sharp rise in gun violence in recent years. But it surely is one of the most lethal.

As The Sun's Justin George reported in a three-part series supported by Marquette University's O'Brien Fellowship in Public Service Journalism, shooting victims in Baltimore are more likely to die than in almost any other city. His analysis focuses on three broad factors to explain the rise in lethality here: the common use of extremely powerful guns, often with oversized ammunition clips; victims whose injuries are beyond the ability of trauma surgeons to repair; and a culture in which violent criminals increasingly shoot to kill rather than merely to intimidate or maim.

We have done what we can about the first two. Maryland has laws specifically designed to make it more difficult for criminals to obtain guns and has banned assault rifles and large ammunition clips, though its efforts are of limited effectiveness given the inaction of Congress and the lax gun control laws in other states. And Baltimore has arguably the finest trauma care system in the United States, thanks to decades of pioneering medical advances and consistent public support and investment.

But the third ingredient Mr. George describes, a culture in which children raised amid violence grow up into killers who attack without conscience, one in which street “rules” to protect the innocent are ignored and potential witnesses are either killed or terrified that they and their families will be, remains vexingly difficult to address. The violence seems to be contagious, spreading from person to person and across neighborhoods like an infectious disease.

There are no quick solutions to a problem whose roots lie in a long history of intractable social ills and injustices — poverty, failing schools, discrimination, joblessness and an insidious drug trade. Both the shooters and their victims have been traumatized by their experiences, and breaking the cycle of violence requires attending to the unaddressed social, emotional and mental health issues that put them all at risk.

Baltimore has had some notable successes in taking a public-health approach to gun violence. The health department's Safe Streets program employs street savvy outreach workers to spot potential conflicts among neighborhood youths and adults and encourage them to settle their differences without resorting to violence. Last year workers mediated some 700 disputes in the four neighborhoods where the program operates; health officials say it defused as many as 300 disputes that might otherwise have erupted in violence. But the initiative needs to be expanded.

Likewise, hospitals that treat gunshot victims can help interrupt the cycle of violence by steering patients into counseling that addresses their emotional trauma as well as their physical wounds. The same principle applies to the city's schools, which are in a unique position to reach out to young people who witness violence or experience it directly, both of which can make them more likely to become perpetrators or victims themselves. This year the health department was awarded a $5 million federal grant to address communities that were affected by last year's civil unrest and another $2.3 million for full-time mental health clinicians in schools. New city schools CEO Sonja Santelises has placed the issue of students traumatized by violence at the heart of her agenda.

Baltimore has made some progress toward getting illegal guns and shooters off the street, though that effort remains far from complete. A much-touted increase in gun arrests has not necessarily translated into convictions and sentences. Witnesses remain reluctant to work with police not just because of intimidation by criminals but also because of the poisoned relationship between the department and many communities, as documented in the Justice Department's scathing report into policing practices in Baltimore. The police commissioner and the next mayor must not flinch from the task of restoring a relationship of trust between city officers and the communities they serve.

Gun violence is a symptom of a vulnerable and long-suffering body politic, trauma is the infectious agent that spreads it, and like any illness one has first to diagnose it and then be open about what it is before it can be treated successfully. None of it will be easy, but it must be done. Lives depend on it.