Four dozen nuclear disarmament activists arrested following die-in at Livermore Lab on anniversary of U.S. atomic bombing of Nagasaki, Japan

Every year, they come with hand-drawn signs and printed posters, with their children and their pets. They protest the past. They pray for peace, and remember the twin atom bombs that the U.S. dropped on Japan at the end of World War II.

But this year, they mostly talked about North Korea and its escalating tensions with the White House over its nuclear missile capabilities.

On Wednesday, 200 protesters gathered outside the gates of the Lawrence Livermore National Laboratory to commemorate the 72nd anniversary of the bomb that decimated Nagasaki, just three days after another atomic blast did the same to Hiroshima. The gathering was heavy with emotion: indignation, outrage and fear over a potential nuclear build-up. The mood was set by verbal threats unleashed by President Trump a day earlier.

On Tuesday, Trump said he would unleash “fire and fury” on North Korea, the likes of which “the world has never seen,” if Pyongyang continued to issue threats against the U.S. The president supplemented his public comments with tweets on Wednesday boasting that the U.S. nuclear arsenal “is now far stronger and more powerful than ever before” and that his first order as president was to “renovate and modernize” the weaponry.

It was the last thing the protesters — from elementary-school-age children carrying posters covered in glitter to the senior citizens in wheelchairs holding “raging granny” signs — wanted to hear.

“We are here to stand with the survivors of that nuclear attack, but we are also here to stop the next nuclear war before it starts,” said Marylia Kelley, executive director of Tri-Valley CAREs, a small advocacy organization formed in 1983 by neighbors living near the Livermore laboratory, one of the nation’s hubs for nuclear weapons research.

“We understand if we are ever going to rid the world of the threat of nuclear war, we need to have the total abolition of weapons,” Kelley said. “There are no right hands for these wrong weapons.”

But putting those words to action, the demonstrators conceded, is not easy.

Photo by Shirley Osgood

Livermore police officials said 47 protesters were arrested at the event on suspicion of civil disobedience.

The event’s speakers, including Pentagon Papers whistle-blower Daniel Ellsberg, stood on a small stage set up in the back of a pickup truck, struggling to be heard over the roar of traffic from a nearby intersection. People in the crowd clasped hands and hollered at every mention of Trump’s tweets in the speeches — an ubiquitous theme.

“What does it mean not to do no harm?” said Janice Kirsch, a doctor and coordinator of the 350 Bay Area Speakers’ Bureau. “You do not plan to fight a nuclear war, and you do not let people know it is possible because that is suicidal and crazy. Deterrence will not work.”

Afterward, the protesters paused for a moment of silence. They closed their eyes and tipped their heads toward the sky. They breathed in the scent of damp grass and fresh-cut hay nearby. And then they marched.

“Clean up Livermore” was written in blue paint on one sign fashioned to look like a missile. “Books not bombs” read another. A woman wearing a yellow headband held a “Plutonium is deadly” poster. Many of the protesters, and even one lapdog, wore green tags around their necks reading, “End war.”

Outside of the laboratory’s gates, they sang, “I’ve been working on the missile all the live long day,” and then lay prone on the street for a die-in. Volunteers traced each others’ bodies in white chalk. A dozen police officers in riot gear watched from the other side of the fence.

Scott Yundt of Livermore said he has come to the protest annually for 12 years. But Wednesday’s felt different and unlike any other, he said.

“Trump’s statements are pushing us closer to the brink of a nuclear war,” he said, standing on the street outside the laboratory. “There’s a palpable and particular fear we are all feeling today. Conflict with North Korea and the United States is possible. I worry our president will press the nuclear button without the consent of the American people.”

Barbara Milazzo, 53, of Mariposa held a framed sign bearing the words “Peace is Patriotic.” In 1986, she walked from Los Angeles to Washington, D.C., with the sign to advocate for peace. She said she was upset the sign had a tangible use again.

“The threats Trump made were chilling last night,” she said. “He is so capable of pushing that button. We are closer to nuclear winter than we have ever been since World War II. Just thinking about it despairs me. I’m thinking, was that the last time I saw my daughter? Have I told my friends and family that I love them?”

She paused, taking in the sight of the protesters gathered outside the gates.

“This is the most we can do,” Milazzo said. “We are using our voices to protest. The rest is out of our control.”

Lizzie Johnson is a San Francisco Chronicle staff writer. Email: ljohnson@sfchronicle.com Twitter: @LizzieJohnsonnn