Party unity may be a tougher sell than some leaders had hoped, if California's delegate breakfast Monday was a harbinger of things to come: Supporters of Sen. Bernie Sanders booed and heckled nearly every speaker at the mention of the Clinton-Kaine ticket.

The breakfast, which featured speeches from House Minority Leader Nancy Pelosi, East Bay Rep. Barbara Lee and California Secretary of State Alex Padilla and others, was surprisingly raucous. Even Lee, a progressive who made it a point not to endorse this year until the primary between Sanders and Clinton was over, was the target of jeers.

But Pelosi wasn't fazed, noting she was a Jerry Brown delegate in 1976 when she and others thought they could take the nomination from Jimmy Carter.

"This is nothing new. People get excited about the campaigns that they are in, and it doesn't turn off the day the determination is made," she said. "You know what? It's the Democratic Party. We have never been a monolith. We have always tried to reach consensus, but unanimity ... is just an impossibility for any party."

Debra Mayes, a Sanders delegate from Los Angeles and a poll worker in the June primary, said she and other Sanders supporters are unhappy with the way the election went. She was among the people chanting "count our votes" as Padilla spoke. She said voter education was almost "nonexistent" -- for example, independent voters didn't understand that they needed to request a Democratic ballot. She added that poll workers in Los Angeles County were improperly trained, and that she witnessed multiple voters being forced to cast a provisional ballot even though they didn't ask to be absentee voters.

She said it's hard to imagine party unity by the end of the week.

"I think our secretary of state was really quite derelict in his job of making sure the election process went smoothly and without the kind of errors and problems that we had," she said.

"This felt like a calculated, orchestrated effort to disenfranchise people to suppress the vote, because he is clearly a Clinton supporter, as is so much of the California delegation and Legislature. This has been quite a corruption of a process that did not have to be the case."

But speaking to reporters after his speech to delegates, Padilla calmly defended California's election process and refuted charges the election was "rigged."

"I love the energy, I love the excitement," Padilla said, referring to the rowdy reception he got. "The best use of that energy is to register voters and turn them out."

Padilla said one of the campaigns (it sounded like he was referring to Bernie Sanders' campaign) told voters not to accept provisional ballots because they would not be counted.

"Absolutely not!," Padilla said. "It's been a very transparent process. Every ballot is counted and accounted for."

As to why the counting took so long, Padilla said it was the result of a progressive reform called "postmark plus three," meaning as long as a mail-in ballot is postmarked by Election Day and arrives by Friday, "it's processed and added to the tally. That's a good thing."

So how long will this show of support for Sanders last? One of his delegates, Kacey Carpenter of Mountain View, said Sanders' delegates won't quit protesting until Clinton officially has the nomination, presumably Tuesday night.

"We came to this breakfast to hear about issues, not to hear that the election is over," Carpenter said. "We want that process completed fairly and honestly and to the very end."

While many here say they expected debate and disagreement, Rachel Binah of Mendocino, an uncommitted superdelegate who likes both Sanders and Clinton, said she found the morning's rowdiness "very concerning to me."

"It's not effective," Binah said. "It's not a very good strategy and it's rude. And it's not necessary. It's not effective to keep being rude to those who agree with us."

Party leaders are hoping tonight's speech by Bernie Sanders will help accelerate the healing process.