THE FOURTH of July, that most American of holidays, is typically celebrated with parades, fireworks and backyard cookouts. In Chicago this year, the holiday weekend was scarred by what tragically has become another American tradition: gun violence.

In the course of 84 hours this past weekend, 82 people were shot in Chicago, 16 of them fatally. One person an hour, not in some far-flung war zone but on the streets of a major U.S. city. “Totally unacceptable” was the judgment of Chicago Mayor Rahm Emanuel. We can only hope that the bloody numbers help in tipping the balance toward eventual enactment of common-sense gun laws.

A tipping point must eventually come for the outsize influence of the gun lobby and the politicians in their thrall: That was the message Monday from Chicago’s weary police superintendent, Garry McCarthy, as he reflected on the city’s deadly weekend. He decried “the illogical nature of what’s happening here.” There’s “overwhelming” evidence that government could reduce the gun violence, he said, but lax federal and state laws and a revolving justice system allow those who commit gun crimes to go largely unpunished.

Police, parents and communities all have to play a part in reducing violence. “As a community we need to demand more of ourselves and our neighbors,” Mr. Emanuel said. For his part, Superintendent McCarthy wondered if a “fatigue factor” among officers deployed over the weekend might have been an issue. Maybe so; but that doesn’t explain how a 14-year-old and a 16-year-old who died in gun battles with police got their hands on a .44-caliber revolver and a semi-automatic handgun, respectively. “The city of Chicago,” as Mr. Emanuel has noted, “does not have a problem of too few guns.”

Chicago wasn’t the only city to experience gun violence over the holiday weekend. A man in Houston opened fire on a crowd at a music festival; seven people were shot in Indianapolis. New York City saw a spate of shootings. It is innocent people in these cities and countless other localities marked by gun violence who must bear the consequences of Congress’s abdication on gun control.

Chicago Mayor Rahm Emanuel listens during a Chicago City Council meeting Wednesday, June 25, 2014, in Chicago. (Brian Jackson/AP)

That is why voters should pay attention to the recently-announced effort of two groups, Everytown for Gun Safety and Moms Demand Action for Gun Sense in America, to have all federal candidates in the 2014 midterm elections answer a survey about their stance on gun issues. When something like Chicago happens, Shannon Watts, founder of Moms Demand Action for Gun Sense in America told us, the National Rifle Association conditions Americans to think there is nothing they can do. “Our message,” she said, “is that they can use their voice, their vote, their wallet,” and they can make a difference.