The issue of gun violence has also been overshadowed by a focus on the nation’s racial tensions after a series of killings of unarmed black men by the police — and underscored by what appear to be the racist motivations of the man charged in the killings at Emanuel African Methodist Episcopal Church in Charleston on Wednesday night.

Senator Bernie Sanders, independent of Vermont and a presidential candidate who has supported control legislation in the past, canceled a campaign stop planned for Sunday and issued a statement saying, “The Charleston church killings are a tragic reminder of the ugly stain of racism that still taints our nation.”

In Charleston on Thursday, a half-block from the church where the shootings occurred, Jack Logan unfurled a banner that read, “Put Down the Guns, Young People.” Jareem Brady, 42, stood talking animatedly next to Mr. Logan’s banner, but said that racial discrimination was a bigger issue than guns. “That’s what this is about,” he said.

The silence is frustrating to some lawmakers. “Justified or not, there has traditionally been a reluctance to talk about policy in the 24 hours after a massive tragedy,” said Senator Christopher S. Murphy, Democrat of Connecticut, who continues to advocate gun legislation. “I really believe that our silence is making us complicit in these murders.”

Americans have sent mixed messages on guns.

A Pew survey last year showed that 52 percent of Americans said they thought it was important to protect gun ownership rights. That figure was up from 29 percent in 2000. In a 2013 poll, Pew found that nearly 75 percent of respondents supported expansion of background checks, which has been the focus of much federal and state legislation.