Bernie Sanders swooped onto a crowd-filled baseball field in Lincoln Park on Monday morning in Los Angeles’ Eastside and shuttled over hours later to Santa Monica, where he made his usual pitches for free college tuition and assailed joblessness and corporate greed.

“A great nation is not judged by the number of billionaires it has or the number of nuclear weapons it has,” Sanders said. “It is judged by how it treats the weakest and most vulnerable among us.”

The Vermont senator has been hopscotching across Southern California ahead of the June 7 primary, adding rallies the way a musician might keep adding concert dates — National City, Vista and Irvine.

He’ll get to Anaheim, Riverside and San Bernardino on Tuesday.

But the presidential hopeful trails Democratic front-runner Hillary Clinton in delegates and would need a combination of a huge win in the Golden State and the flipping of superdelegates from the former secretary of state’s column to his to win the nomination.

Both rallies on Monday featured Sanders offering a bold prediction saying, “We are going to win the state of California.” But a new poll makes that prediction unlikely: He faces an 18 percentage-point gap with Clinton among voters likely to participate in the Democratic primary, according to the ABC7-Southern California News Group poll released Monday.

Still, Sanders insisted “we are going to win the state of California because by the end of this campaign, we are going to have rallies all over this state and speak personally in a grass-roots way to over 200,000 people.”

Sanders estimated that 5 million people would be voting in the Democratic primary and that he’ll need at least 2.5 million voters to cast ballots for him. The 200,000 direct contacts through rallies, he said, is an “unprecedented” effort in California primary politics.

• PHOTOS: Bernie Sanders holds Lincoln Park rally in Los Angeles

Sanders’ L.A. visit was a last-minute add to his schedule. The campaign set up a stage on a baseball infield at Lincoln Park, with the podium set near the pitcher’s mound and supporters fenced in deep to the edge of the grass leading to the outfield. Behind Sanders a banner read, “A Future to Believe In.” It was set between an American flag and the state flag.

The rally at Santa Monica High School’s stadium began just as the sun dipped. It also came as the Clinton campaign finally told Sanders there would be no debate between the two Democrats, something he has repeatedly been pushing.

“It’s a little bit insulting,” he told the crowd in Santa Monica.

His speeches also took aim at Clinton for her claims that she is already the presumptive nominee, and her name elicited boos from the crowd. But the boos reached a crescendo at the Lincoln Park rally when he brought up the Republican’s presumptive presidential nominee, Donald Trump.

“Donald Trump is not going to become president of the United States,” he said.

A couple of thousand people attended the Monday morning rally, carrying signs, waving banners and maintaining hope that Sanders could still win the nomination.

People like Gabby Scott.

“I’ve never thought of any other outcome other than Bernie,” Scott said. “I’m just as hopeful as I was when I first learned about him.”

The 27-year-old from Los Angeles, wearing four buttons and a Sanders T-shirt with another one draped over her shoulder, said she has been working on her family and one friend — a Clinton backer — to vote for Sanders.

“I’ve had more success with my family, other than my Republican dad,” she said.

Scott planned to vote next month, though Monday was a critical day for both campaigns: the last day to register to cast a ballot in the primary. It also marked a busy week for the campaigns as they continued to ramp up appearances in California in search of the state’s 475 delegates.

Clinton was in Los Angeles on Monday for fund- raisers and will have an appearance with Rep. Karen Bass Tuesday before speaking at a rally in Riverside that afternoon. Her campaign also opened its ninth office in California in Woodland Hills.

Meanwhile, Trump will travel to Los Angeles on Wednesday for a fundraiser hosted by longtime friend Thomas Barrack, a private equity investor who is the founder, chairman and chief executive officer of Los Angeles-based Colony Capital.

Trump will then hold an event at the Anaheim Convention Center at noon Wednesday.