"We know that there are many among us who want to tackle the very real threat posed by the political far right, which is growing emboldened in Washington, D.C., and in the streets of Berkeley," the group posted on Facebook
"Mass mobilization, organization, and commitment to the politics of solidarity can actually confront the far right threat and defend our rights to free speech and assembly."
Hundreds of people gathered in Sproul Plaza -- the epicenter of Berkeley's free speech movement -- as one man blasted Coulter over a megaphone.
"This is not about free speech. This is about fascism," he said.
About 10 feet away, a Coulter supporter waved an American flag, saying the issue was indeed free speech and that the university was denying conservatives their rights.
About 70 law enforcement officers, most dressed in navy uniforms and wearing ball caps, stood in groups, watching the 150 or so people who milled about while other students traversed the plaza in between classes.
Most of the officers had riot helmets and zip ties hanging from their belts, but there was little tension. Thirty more police officers arrived about noon.
Some people brought signs. Several bore the slogan, "No! In the name of humanity, we refuse to accept a fascist America."
Campus police said there had been two arrests.
"Both individuals' affiliation to UC Berkeley is unknown," the university tweeted.
'Freedom of Speech' rally
Conservative commentators on Thursday afternoon converged at the Martin Luther King Jr. Civic Center Park, a city park several blocks from the campus.
Several hundred people came to hear the speeches. Alt-right activist Brittany Pettibone
drew a big cheer when she said the right refuses to stand down.
"Let's show them ... what freedom of speech means to the right," she said.
Gavin McInnes, a controversial right-leaning online talk-show host, delivered Coulter's speech, which was about immigration.
"Immigrants are showing up with a lot of needs and a lot of grievances. Why do we owe them? If you have grievances go home and address the perpetrators. We owe you nothing. By my reckoning, they owe us," Coulter would have said, according to McInnes.
Coulter told Fox News on Thursday night that the point of the speech was that laws written by Republicans and Democrats need to be enforced.
Several attendees draped American flags over their shoulders.
Joey Gibson, 33, had traveled from Vancouver, Washington to be there, along with a dozen members of a group called American Freedom Keepers. He wore a Trump-Pence Infowars shirt, an American flag bandanna and a motorcycle helmet with goggles.
Gibson said the group came to Berkeley to protect the speakers. "If the police do their job today, we can just sit here and watch," he said, adding that he and his friends were not there to provoke or instigate.
"A great day would be a day where antifa could come up and do their chants ... we could hear the people who want to speak without the worry of violence and we could all go our own ways."
Rumors that antifa supporters had arrived about 30 minutes into the speeches changed the mood in the crowd, and some attendees took defensive postures near the speakers. There were anti-Trump demonstrators on the other side of the street. Some held a banner that said, "Trump must go. By any means necessary."
After the event wound down, the two sides yelled across the roadway at the others, while helmeted police formed two lines in the middle of the street.
"Hey, hey! Ho, ho! Donald Trump must go!" counter-demonstrators yelled.
"Don't listen to people telling you to hate us and Donald Trump," one person on the other side shouted. "Think for yourself."
She said, he said
Exactly who canceled Coulter's speech remains a point of contention.
The Berkeley College Republicans
and Young America's Foundation
are suing the university, accusing the school of discriminating against conservative guest speakers by placing onerous time and location restrictions on their appearances.
Coulter gave her account of events on Twitter, claiming the Young America's Foundation did little to stop the cancellation.
"I'm so sorry Berkeley canceled my speech. I'm so sorry YAF acquiesced in the cancellation. And I'm so sorry for free speech crushed by thugs," she said. "It's sickening when a radical thuggish institution like Berkeley can so easily snuff out the cherished American right to free speech."
But a university spokesman said organizers of the speech didn't follow proper protocol and that the speech was never formally scheduled.
"Ms. Coulter and speakers regardless of their position are welcome on this campus," spokesman Dan Mogulof said.
He said the school asks for two months' notice of an event so it can work out logistics and security. The school was tentatively notified by an email in mid-March that said the group was hoping to get Coulter to appear in late April or in the fall.
No specific date was discussed, he said.
University officials learned of the event being scheduled for April 27 when they read about it in a newspaper, he said.
The school scrambled to find a venue, Mogulof said.
"We know how to do this, but we can't do what we want to do to facilitate those speakers if the groups that want to invite them and host them don't work with us in the way that they need to," he said.