Campaigning in San Francisco Monday, Sanders declined to speculate to reporters about what a poor showing in Tuesday’s primaries might mean to his presidential campaign. “Let me just talk to you after the primary here in California where we hope to win. Let’s assess where we are after tomorrow,” he said.

Hours later, at an evening rally at Crissy Field in the Presidio, Sanders steered clear of reports from The Associated Press and multiple television networks that Clinton had reached the 2,383 delegates needed to become the presumptive Democratic nominee. She has 1,812 pledged delegates won in primaries and caucuses, and the support of 571 superdelegates.

Sanders’ supporters expressed disappointment that the calls were made before California’s primary and urged the senator to continue on despite the pronouncements.

“We’re going to keep fighting until the last vote is counted,” said Kristen Elliott, a Sanders’ supporter from San Francisco who attended the rally.

Said another attendee, Patrick Bryant of San Francisco: “It’s what bookies do. They call fights before they’re over.”

He said the campaign’s job is to convince the superdelegates that the Vermont senator is “by far the strongest candidate against Donald Trump.” He said calling the Democratic contest before superdelegates formally vote at the convention was a “rush to judgment.”

Sanders spokesman Michael Briggs said Clinton’s support was dependent upon superdelegates who could still change their minds between now and the July convention.

Sanders’ tone was more subdued before reporters after saying over the weekend that the Democratic convention would be contested if no one wins the nomination based solely on delegates awarded in the primaries and caucuses. Sanders also faced new questions about the future of his campaign amid reports that President Barack Obama was readying an endorsement of Clinton.

Sanders and Clinton are competing in contests in six states on Tuesday, headlined by California, the nation’s largest state, offering 475 pledged delegates. Clinton, a former New York senator, is heavily favored in Tuesday’s New Jersey primary and winning a share of the state’s 142 pledged delegates would likely put her over the top.

Obama, who bested Clinton in 2008 during her first bid for the Democratic nomination, is preparing to formally endorse her and start aggressively making the case against Trump. White House officials said the announcement could come within days, although not before Tuesday’s elections.

Obama called Sanders on Sunday as he campaigned in California, a Democrat familiar with the call told The Associated Press. The person spoke on condition of anonymity because the person was not authorized to discuss the private conversation, and would not reveal any details about it.

Asked by reporters in San Francisco if he had talked to Obama, Sanders demurred. “I have spoken to President Obama many, many times about many issues, and I really think it’s not appropriate to talk about my discussions with the president,” he said. “I try to keep that private.”

Sanders, a self-described democratic socialist, who has won 20 states and pushed the heavily favored Clinton for the nomination, has outlined plans to influence the party platform and try to persuade superdelegates that he would fare better than Clinton against presumptive Republican nominee Donald Trump.

Sanders has previously said that Clinton should not be deemed the party’s nominee because she would be relying on superdelegates — party officials and elected leaders — who do not actually vote until the Democratic National Convention.

[fortune-brightcove videoid=4924709684001]

But he did not make that case to reporters Monday, instead focusing on Tuesday’s outcome. Rallying supporters at City College of San Francisco’s Mission Center, Sanders said Clinton’s voters were more reliable and he would need a large turnout among recently registered voters, independents and young people.

While Clinton has been in the driver’s seat for the nomination for weeks, a victory by the front-runner in California would give Sanders much less leverage as he seeks to sway superdelegates.

Sanders has campaigned intensively in California for more than two weeks straight, blanketing the state with rallies and events in 34 cities aimed at talking directly to thousands of voters at a time.

He capped the day with a concert rally featuring singer Dave Matthews and then was traveling to Los Angeles on Tuesday for the primary. Sanders said he would return home to Vermont on Wednesday.