PLENTY OF BLAME TO GO AROUND:

The volatile tribalism now so ingrained in American life will eventually right itself, says Robb Willer, a sociology professor at Stanford University, but not until the public decides it's had enough and stops rewarding politicians who use incendiary language and demonize the other side. It's impossible to guess, he notes, how much damage will be done in the meantime.

"That is the question of our time: Are we going to choose to continue the war, or are we going to choose peace? And we don't know yet what the answer to that will be, because while a majority of Americans are fed up with the extremity of our political divisions, it does feel like we're stuck here," Willer says. "It will get worse before it gets better."

Animosity between parties has been growing for decades now, to the point that studies show Republicans and Democrats don't want to date one another, don't want their children to marry one another and don't want to live in the same neighborhoods at a rate unprecedented in modern America. At the same time, politicians began using increasingly apocalyptic language. Willer says those two forces -- the splintering of society along party lines and the ascent of vitriolic campaigning -- merged to create a breeding ground for violence.

"It was simmering," says Parker. "It's like the gas burner was on, then Trump lit the fire."

The president vaulted to political prominence by promoting the racist and false conspiracy theory that Obama was not born in the United States, launched his presidential campaign by calling Mexicans rapists and murderers, and routinely describes his enemies, including the intended recipients of the pipe bombs, as "evil," ″dangerous," ″the enemy of the American people." [...]

"America is resilient; we find a way even in our darkest days," 36-year-old Cordell Lawrence said as he voted last week in Louisville. Lawrence described himself only as a moderate, preferring not to make public what party he leans to because he worries that could hinder personal and professional relationships.

"Maybe we have to hit rock bottom before we find how to get back up," he said. "We're probably pretty close to rock bottom today. At least I hope we are."

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