In South Florida, not far from the mass shooting in Parkland in February, voters absorbed a week of gun violence and pipe bombs with a kind of grim resignation.

“Again?” asked Karenn Durand, 27, mid-shift at a restaurant in North Miami on Saturday, pondering the mass murder at a Pittsburgh synagogue. She said she held President Trump personally responsible — if not for the shooting itself, then at least for the nation’s deep divisions that the shooting reflected in horrific reality.

In Milwaukee, Eric Pfeiler, an electrician who was walking downtown with his son on Saturday, saw more of a systemic breakdown than any one person to blame.

“There’s just so much turmoil everywhere, it’s just sad,” Mr. Pfeiler said. “Everyone’s lost their vision and has just started pointing fingers.”

And at Mr. Trump’s rally on Saturday afternoon at an airport hangar in Murphysboro, Ill., people expressed anxieties over the violence and discord they saw in American society. But they had come for a Trump rally performance, and that was what they wanted to see. When he begged their forgiveness and asked them at one point, “If you don’t mind, I’m going to tone it down — just a little,” many people roared a resounding “No!”

With nine days left in an already divisive election season, the campaign’s finale is unfolding amid a cascade of horrors and rounds of finger-pointing that reflect the deep fault lines in dozens of competitive House races and a handful of Senate races nationwide. If many voters appear set to back politicians from their own parties, according to interviews and polling, they also often defended or blamed politicians — particularly Mr. Trump — based on the same partisan lines.

On Friday, Cesar Sayoc Jr., 56, was charged with sending explosive devices to at least a dozen of Mr. Trump’s political foes. On Saturday, Robert Bowers was arrested and charged with 29 criminal counts in connection with the assault on a Pittsburgh synagogue that left 11 dead. Near Louisville, Ky., in an episode almost immediately forgotten, Gregory Bush, 51, was charged with murder after fatally shooting two black shoppers at a Kroger store on Wednesday after first trying to get inside a black church. Mr. Bush is white and the case is being investigated as a possible hate crime.

In Florida on Saturday, hours after the synagogue shooting, Eric Gooden, a Democratic voter, hoped for an electoral solution to the turmoil. “The only way this will end is by the voting box,” he said.