Callers fuming over the University of Nebraska-Lincoln’s plans to host 1960s and ’70s radical William Ayers as a speaker next month warned there would be “hell to pay” if he wasn’t disinvited, according to a memo prepared by a campus threat assessment expert.

The university released the three-page memo from psychology associate professor Mario Scalora on Wednesday. The memo shows callers, e-mailers and bloggers threatened to disrupt Ayers’ speech, stage protests or harm — and even kill — Ayers if he came to Lincoln.

“I hate violence, but I think that any directed at Ayers would be well deserved,” one blogger wrote.

“I wonder what kind of flag (Ayers) wants on his coffin,” wrote another.

And several callers said Ayers deserved to be treated as a terrorist, not an American citizen.

Overall, the university received more than 1,000 e-mails and phone calls protesting the visit.

Given such an overwhelming and intense public reaction, Scalora wrote, UNL faced “significant concerns regarding security” if Ayers’ Nov. 15 keynote speech at the College of Education and Human Sciences student research conference was to go on as planned.

“We can be assured that we will have groups and frustrated individuals who will attempt to disrupt the event and attempt to be provocative toward Ayers and others in attendance,” Scalora’s memo read.

He sent versions of the memo to UNL Police Chief Owen Yardley and Chancellor Harvey Perlman on Thursday, the same day UNL announced Ayers’ planned visit.

By Thursday night, Perlman — who was wrapping up a two-week trip in China — had decided to cancel the Ayers speech.

UNL waited until Friday evening to announce the cancellation because officials first had to reach Ayers, who was in Taiwan.

By then, public condemnations of the invitation had poured in from Gov. Dave Heineman, Attorney General Jon Bruning, congressional leaders and others, leading some UNL faculty to wonder whether Perlman had caved to political pressure.

Perlman has said his decision was security-related.

It’s a decision Scalora said he supports, though he said in an interview Perlman was caught in “a difficult and unenviable position.”

“This has been a very challenging and messy time for all of us,” Scalora said.

Ayers, an education professor at the University of Illinois at Chicago, had been selected by a UNL faculty committee in February to speak at the student research conference, which comes during a two-day celebration of the education college’s 100th anniversary.

Ayers, who has authored numerous scholarly articles and books, was chosen for his expertise in topics like social justice and urban educational reform.

Faculty couldn’t have predicted in February, Perlman has said, that Ayers was about to become such a controversial figure in the presidential campaign.

Ayers was a founder of Weather Underground, the group that claimed responsibility for the bombings of public buildings in protest of the Vietnam War. Years later, he and Democratic presidential nominee Sen. Barack Obama served together on the board of an anti-poverty nonprofit in Chicago.

Ayers’ speech at UNL, scheduled at the Teachers College, was to have been open to faculty and students only.

But given the widespread public furor over his invitation, Scalora’s memo said, if UNL wanted to stick with Ayers, it would need to change the venue, coordinate with local and state law enforcement and beef up security personnel during the event.

All that would have been difficult to do in less than a month’s time, Scalora said Wednesday.

“Do we go to Cops ’R Us to get all that?” he said. “In a short time, you can’t pull together a large number of security resources.”

In fact, he said, UNL’s threat assessment team continues to evaluate whether security may still be needed during the education college’s centennial celebration, as protesters may show up because Ayers was invited at all.

“We just don’t know,” Scalora said. “We’ll have a better sense as we get closer.”

Reach Melissa Lee at 473-2682 or mlee@journalstar.com.