A series of escalating confrontations during a summer of protest has inflamed political tensions in Minnesota and across the nation, sparking concerns about civility and the bounds of political debate as a national reckoning over race and police brutality collides with a heated presidential campaign.

In the Twin Cities, protesters representing a mix of agendas have taken to marching on officials' homes: The targets have ranged from Minneapolis Mayor Jacob Frey and GOP state Sen. Warren Limmer to the head of the Minneapolis police union. Earlier in the summer, pro-Trump supporters rallied at the State Capitol with guns, following a pattern of intimidation seen at state capitols in Michigan and Virginia.

Confrontations elsewhere ended in bloodshed in recent weeks as a pro-Trump vigilante killed two protesters and wounded a third in a night of demonstrations over the police shooting of Jacob Blake in Kenosha, Wis. In Portland, Ore., a far-right militia member was fatally shot by a man who said he was providing security to protesters as Trump supporters and leftist demonstrators clashed in the streets. Kenosha became a campaign stop for both major-party candidates last week.

Some see the clashes as a symptom of a growing tribalism in American politics that has brought social tensions to new heights.

"There's no question we have a divided nation today," said Mike Erlandson, a former DFL Party chair. "Something like riots in the streets, nobody really knows how to process that."

Much of the recent tension traces to the Minneapolis police killing of George Floyd, which sparked protests around the globe and helped frame a new era of politics and election-year divisions. Some hearkens back to the August 2017 march by armed white nationalists in Charlottesville, Va., where a self-described neo-Nazi ran his car into a crowd of counterprotesters, killing a woman.

President Donald Trump has blamed Democrats for enabling "thugs" and "anarchists" responsible for episodes of rioting, looting and arson. Democratic presidential candidate Joe Biden has accused Trump of stoking the unrest by vilifying protesters.

Whichever narrative sticks, political discord has taken a new and personal twist around the Twin Cities.

An August rally outside the Hugo home of Lt. Bob Kroll, president of the Minneapolis Police Federation, sparked condemnation from both parties after activist John Thompson, a DFL legislative candidate, was filmed shouting expletives and saying he didn't care if the suburban city burned. Protesters, including Thompson, beat piñatas depicting Kroll and his wife, a Twin Cities television journalist. Thompson, who apologized, has said his family has received death threats since the incident.

The confrontations have activists and politicians across Minnesota on edge. At least one local official whose house was targeted and vandalized is planning to move. Fears of harassment and violence prompted about a third of the Minnesota GOP delegates to the national convention to ask that their names not be made public.

In Minneapolis, protesters against police brutality and racism have ramped up pressure on liberal leaders and other local officials. Makeshift tombstones listing the names of people killed by law enforcement and calls to defund the police appeared in the yards of some City Council members. Days after Floyd's death, more than 1,000 protesters gathered outside the home of Hennepin County Attorney Mike Freeman to urge him to press charges against the officers involved, throwing streamers in trees and sitting on his lawn.

More demonstrations followed through the summer. In July, a group of activists gathered at the stoop of Limmer's home, banging on the door to demand he come out and address their concerns. Limmer, a Republican state senator, called it unnerving. It was the second time this year protesters had come to his home.

"You get a different feeling when you see people slithering up to my front door, opening it and then pounding and yelling, demanding that I come out to greet the mob," Limmer told Fox News. "And it really isn't anything — that type of thing, no one in America should experience."

Gregg Peppin, a GOP strategist, said he has seen a steady progression of animosity, anger and "inability to have civil conversation" about politics. The trend has led to "a higher level of concern about personal safety" at campaign events, he said, citing a recent incident in which a man with DFL ties interrupted a campaign movie screening with an obscenity-laced outburst.

"I think that a person's house should be off limits. I think a person's family should be off limits. Unless they're a political figure, if they're a private individual, their job should be off limits," Peppin said. "We've crossed those lines. Everyone needs to dial it back."

Leaders on both ends of the political spectrum have condemned the looting and destruction that emerged amid the protests this summer in Minneapolis and other cities. But they also traded the blame over root causes of the unrest.

Democrats say divisive racial rhetoric from the president has emboldened vigilantes on the right. They point to Trump's comments blasting protests and his reluctance to condemn right-wing violence and the shooting in Kenosha.

"When [violence] isn't condemned, that sends a message to those who are looking, hey we have free rein there," said Ron Harris, a Democratic National Committee member from Minneapolis.

Republicans say activists on the left are taking things too far. Jennifer Carnahan, chair of the Minnesota Republican Party, recounted being surrounded by "vitriolic" protesters outside the White House after attending Trump's acceptance speech during the Republican National Convention. "Many of the people were scared to actually exit the gates," she said. "They were screaming, swearing at people."

Activists involved with some of the protests in Minnesota have said they are driven by frustration about a lack of engagement from officials.

Harris, the DNC member, said the approach likely reflects the degree to which people are fed up with a political failure to address issues of systemic racism and oppression.

"All the other venues for change have not worked for them," he said. "What else are they supposed to do?"

City Council President Lisa Bender said if anything, actions at policymakers' homes make them "less likely to react to the demands or communications from a group of people." She noted that some of her colleagues have received death threats, triggering personal protection from the city.

It's not just Minneapolis. In Seattle, New York and Los Angeles, protesters have shown up outside the homes of elected officials or police chiefs. The Chicago Tribune reported that police there arrested people for protesting near Mayor Lori Lightfoot's home, raising concerns from First Amendment advocates.

Kenza Hadj-Moussa, of the progressive group TakeAction Minnesota, said the divisive tone from the White House, coupled with the stress and isolation of the pandemic, has created a "perfect storm" for uprisings this summer. Without access to public spaces typically used to protest, including the fenced-up State Capitol, she said "people are looking to go where their opinions can be heard."

But she also acknowledges that the at-home protests have been "extremely stressful" for elected officials. TakeAction has not been involved in those.

"We want good leaders to be in elected office. If they're not able to do that and have peace of mind with their family, we can't have that," she said. "Vandalism shouldn't be tolerated. It certainly is not a way to sway an elected official's mind."