Do something.

It doesn’t have the ring of a rallying cry, but that is, in fact, what is being chanted, starting with the response of mourners at a vigil for the nine slain in the Dayton, Ohio, mass shooting. It all but drowned out the remarks of Ohio Gov. Mike DeWine.

This could be the occasion to offer a long-awaited response to that cry, if American leaders can overcome their reticence to deal with what has become a shameful capitulation to violence.

Across the country — even in Hawaii, where existing strict gun laws have caused the issue to recede from the public agenda — those watching the aftermath of the violence were moved.

The Ohio massacre, carried out early Sunday, came a mere 13 hours after 22 people had been slaughtered in El Paso, Texas. Police, who quickly killed the Dayton gunman, are searching for a motive; the shooter in the Texas attack, who is in custody, is suspected to be a white supremacist.

The two events seem entirely unrelated, but the fact that they occurred in such rapid succession has stunned many people who otherwise have grown habituated to the episodic killing sprees.

Other than watching for the death toll to tick up, sickeningly, the country seems powerless to decide what should be its next move.

It doesn’t have to be this way. As the quickening pace of these horror stories makes them seem more like an epidemic than an anomaly, Americans are confronting the disgrace and are pointing to actions that should have been taken long ago.

One would be to give a measure, H.R. 8, the Bipartisan Background Checks Act of 2019, the hearing it deserves in the U.S. Senate. The legislation, which would require background checks for person-to-person firearm transfers, already has passed the House, and this should be its moment to advance further.

New state “red flag” laws comprise another route, one that seems to be gaining traction. These laws give the public the means to warn authorities about someone at serious risk of causing harm.

Republican Sen. Lindsey Graham has paired with Democratic Sen. Richard Blumenthal to create a federal program assisting states in enacting red-flag laws.

Would that approach work better than a federal law? Possibly: States would have the opportunity to impose safeguards to ensure the law does not abuse due-process rights.

The fact is, almost any action would be helpful in breaking the inertia that seemingly has paralyzed elected officials at the congressional level.

In particular, background checks do have popular support, if polls are to be believed. According to an NPR/PBS NewsHour/Marist poll taken July 15-17 of 1,346 adults nationwide, 89% believe background checks for gun purchases at gun shows or other private sales would be a good idea.

However, the fact remains that those concerned about the Second Amendment of the U.S. Constitution, with its protections for gun rights, are more likely to vote on the basis of that single issue than are those who favor controls. Until that dynamic changes, the policymaking is liable to be stuck.

Hawaii has background-check requirements already and in June enacted its own red-flag law enabling family members, co-workers or police to obtain court orders blocking access to firearms for people posing a threat due to mental illness or other causes that arose after they acquired a gun.

This gets at a central argument gun-law opponents cite: Gun control constrains law-abiding citizens, not criminals. The answer: Some gun owners are law-abiding citizens until they become criminals, for reasons not entirely understood, by engaging in mass killing.

It’s at this point that it is, without the shadow of a doubt, time to “do something.”