The threat of California’s progressive boo birds is reason enough for Joe Biden to skip the state’s giant Democratic Party convention next week.

But the added layer of risk in getting onstage with Jorge Ramos, the immigration rights-crusading Univision news anchor and moderator of a candidate forum at the convention, also played a role in the campaign’s discussions about skipping the largest single state gathering of Democrats.

Ramos, who is supposed to hold 15-minute conversations onstage with each top candidate in front of the crowd, has a history with Biden. He emerged as a tough critic of Obama administration immigration policy and has already aggressively confronted Biden during the primary over the issue, which has repeatedly tripped up the former vice president.

As a moderator of the September presidential debate, Ramos flustered Biden by asking if Latinos should trust him and by repeatedly pressing the former vice president to explain President Obama’s record of deporting 3 million people. Ramos noted at the time that Biden never explained whether the deportations were a mistake. After the debate, the two reportedly had a contentious private discussion about the exchange.

Biden’s camp as well as some neutral Democratic observers are convinced Ramos would look for a similar moment at the convention, which will be packed with progressive immigration activists.

“We have a history in California with respect to candidates getting booed,” said Garry South, a veteran of 21 conventions and four gubernatorial races in the state, pointing out that John Kerry and Joe Lieberman were booed in 2004 as well as Sen. Dianne Feinstein when she ran for governor in 1990. In June, Democratic presidential candidates John Hickenlooper and John Delaney were booed for criticizing socialism and Medicare for All, respectively.

“I don’t really think that Biden’s got the imperative to talk at the convention and get at best a lukewarm reception from some activists and where he risks getting booed and then attacked on stage over his record,” South, who is neutral in the race, said. “The delegates at these conventions are not really reflective of the broader electorate or the typical Democratic voter in California. They are the activists of the activists.”

Officially, Biden’s presidential campaign cited scheduling conflicts in other states to explain why he’s skipping the Nov. 15-17 California convention — the third Democratic meeting in the state he has missed since summer. Sen. Elizabeth Warren, who attended the other California meetings, has also announced she would skip the convention.

But the penchant of California’s progressive activists to give moderate candidates a rude greeting played a key role in keeping Biden away, advisers to Biden’s campaign and fundraisers said, describing the venues as high risk and low reward.

A Democratic consultant familiar with the Biden campaign strategy echoed the sentiments about the convention activists and said Biden would prefer to campaign earlier in California at a separate event, Washington and then in early-state Nevada.

“It’s not that we’re scared. But we’re not stupid,” the Democrat, who was not authorized by the campaign to speak, said. “One could argue that some of the activists at the California Democratic Party’s convention are not the best reflection of California’s Democratic voters. It has skewed way more progressive. And we want to speak to the voters at our events that have real engagement.”

As for Ramos, the adviser pointed out, Biden is friendly with him and even employed his daughter when he was vice president: “Jorge Ramos knows the vice president very well. I’ve heard other people say ‘well, he doesn’t want to talk to Jorge.’ We’re not scared of Jorge Ramos. We just have other events.”

Still, Obama loyalists and Biden backers bristle quietly about how Ramos popularized the term “deporter in chief” to describe the former president’s record. And they believe that, contrary to what immigration activists or Ramos say about Biden’s record, the former vice president is well-positioned to win the state and Latino voters more broadly. A new poll shows Biden leads the field nationally among Latino Democrats.

“California Hispanic Democrats – who largely live from Inland Empire/LA up through [Interstate 5] and into Sacramento – are among the most moderate Democratic voters in California. Ramos does not represent any of them,” said one California donor and adviser to the Biden campaign. “So if he gets up on stage and says ‘blah, blah, blah, deporter-in-chief’ when he’s being a grandstander-in-chief, well, we’re not going to do great with that guy. But we’re going to do great with the electorate.”

The donor advised Biden’s campaign to skip the convention, saying it has too many progressive activists hostile to moderates and “hard white left socialists and — not Democratic socialists — real socialists; 23-year-old white guys who still wear Che Guevara T-shirts.”

“He would be stepping into the shark tank. There’s no interest or ability to keep some collective, good behavior. You could get in and out without too much damage, but there’s no upside,” the donor said.

Said another California donor who talks to the campaign: “All of us were against Biden going. I said, ‘I will stand outside and keep you from walking in if it keeps you from going in.”

A spokesman for Univision, Jorge Zamora, expressed pride in the network’s anchor, who has gotten under the skins of Biden as well as presidents Obama and Trump, Sen. Marco Rubio and Venezuelan dictator Nicolas Maduro.

“Jorge Ramos is simply a relentless interrogator of power, no matter who wields it,” Zamora said. “He exemplifies journalism at its best, speaking truth to power, asking tough questions and holding politicians accountable. That is what journalism is all about.”

In a written statement about Biden’s California plans, the campaign said that “Biden is looking forward to returning to the West Coast next week to hear directly from voters and talk about his vision for addressing their most pressing concerns … Californians play a crucial role in the Democratic primary, and no one will work harder to earn their vote and ensure we defeat Donald Trump next November.”

South and others say Warren — who will also miss the convention — wouldn’t have faced the same level of hostility as Biden. She’s not only a darling of progressives, she attended the state’s last Democratic gathering without incident.

Still, after Warren announced her decision Tuesday not to attend, California Democratic Party Chair Rusty Hicks excoriated her and Biden, who had made his decision late last month.

“I respect your work/candidacy, BUT… you should reconsider your misguided decision to publicly snub California’s Democrats & Latino Voters across the nation,” Hicks wrote in Facebook and Twitter posts aimed at the two.

“Your decision is a blatant disregard and disrespect to California’s grassroots leaders who make the phone calls, knock the doors, and give the money… in swing districts and swing states alike… year after year after year.”

But most Democrats are taking a pragmatic view of the no-shows, especially Biden‘s absence, according to Christine Pelosi, who heads the California Democratic Party women’s caucus and is the daughter of House Speaker Nancy Pelosi.

“I don’t know that there are that many undecided people who worry if a candidate is not there,’’ she said. “I also think that the frontrunners have a different strategy — which is, ‘Am I going to spend my afternoon getting heckled by supporters of my opponent — or am I going to build my campaign?‘”

Pelosi said the risks to Biden could be too great because “having a forum at a California Democratic Party convention — you’re just asking yourself to get booed, to get heckled … If I were a candidate, I’d rather do my five minutes, say my piece and move on, rather than sit there as people decide this is going to be their performative moment to try and shut me down.”

Carla Marinucci contributed to this report.