Bernie Sanders speaks during a news conference on health care on May 31, in Emeryville, Calif. (Justin Sullivan/Getty Images)

EMERYVILLE, Calif. — With just one week to go before this state's primary, supporters of Sen. Bernie Sanders are starting to ask whether media coverage will skew results by declaring Hillary Clinton the presumptive nominee of the Democratic Party.

"Here's what's really bad," said RoseAnn DeMoro, the executive director of the pro-Sanders union National Nurses United, after the candidate held an event with its members. "At 5 o'clock, evidently, there's this plan for the media, if Clinton wins New Jersey, to say: 'This is over. She's got it locked up.' That's a lie. That's a lie."

"It's a lie," a nurse in the audience said loudly.

DeMoro was referring to not-so-secret plans for media outlets, which have been keeping their own delegate counts, to mark the moment when Clinton wins the 2,383 delegates needed to clinch the nomination. The Associated Press's count, the basis for many other media outlets, has Clinton at 2,312 — 1,769 won in primaries and 543 superdelegates. There are 12 delegates up for grabs in the U.S. Virgin Islands on June 4, and 67 more in Puerto Rico the next day. At her current pace, Clinton would hit the 2,383 target on June 7 at 8 p.m. Eastern time, when polls close in New Jersey and the state's 142 delegates are parceled out.

"This is what I call trouble, what I'm about to start here," Chris Matthews said on MSNBC last week. "At 8 o'clock that night, Eastern time, the networks — including this one — will be prepared to declare that Hillary has won."

In 2008, Democrats faced a similar scenario when the results of South Dakota's primary — a surprise loss for Barack Obama — nonetheless put him over the top. That count, like the current one, factored in the superdelegates who had started to break for Obama over Clinton. But in that year's front-loaded schedule, California had already voted. This year, the idea of a call that would come at 8 p.m. Eastern (5 p.m. in California) has infuriated Sanders supporters, many of whom argue that the superdelegates don't "count" until the party's convention in July.

"It'll depress turnout on both sides," Sanders campaign manager Jeff Weaver said in the same MSNBC segment where Matthews explained the probable call. "It'll be an inaccurate description of the race, because all we have from superdelegates is essentially a poll."

Shaun King, a Black Lives Matter activist who campaigned for Sanders in New York, wrote in the New York Daily News that the June 7 call would make the race look "rigged," and that "counting what people are promising to do 45 days before they have done it would be like calling a state for Hillary Clinton in late February when it doesn't actually vote until early April."

Seth Abramson, an academic who has become a popular pro-Sanders columnist at the Huffington Post, warned that "the networks will make the news on June 7th rather than report it."

At the National Nurses United event, the "5 p.m. call" was not just described as unfair. It was a hint that the Democrats would hand the nomination to a candidate who polls worse than Sanders against Donald Trump. DeMoro led the crowd in a chant of "Only Bernie Sanders can beat Donald Trump," and warned that progressives across the state would suffer under an early call.

"So, the idea is that people in California — working people who are getting off work — would think it's over," she said. "And it wouldn't be over. Not only would it discourage Bernie voters, but all of the other progressive candidates downballot would be disadvantaged, because voters would think it's over."

In a video posted by his campaign, Democratic presidential candidate Bernie Sanders appeals to California voters ahead of the state's June 7 primary. (Bernie Sanders)

In 1980, an early call did depress some of California's turnout. Surprised by the breadth of Ronald Reagan's victory, President Jimmy Carter conceded with a phone call at 9:01 p.m. Eastern time — the earliest concession since 1904. Polls were still open across the West, and Democrats lost Senate races in Arizona and Idaho by razor-thin margins, a result some of them blamed on depressed voters going home rather than casting a futile Carter vote.

The stakes would be lower on June 7, but that has not soothed the Sanders supporters now thinking nervously about TV screens flashing "Hillary Clinton wins" right when they're making their final drive for votes.

"It would be a horrible injustice," said DeAnn McEwen, 64, a nurse who attended Tuesday's event. "It would be like me saying: Okay, you're going into the ER for cancer surgery. We're going to put you through this, but we're not going to be able to get it out."