SACRAMENTO — A man active in the campaign against mandatory childhood vaccinations was arrested Wednesday after he streamed himself live on Facebook shoving state Sen. Richard Pan, who is carrying a bill to tighten the rules for obtaining a medical exemption from the shots required by California schools.

The Sacramento Police Department said it cited Kenneth Austin Bennett, 54, for misdemeanor battery and released him. The Facebook live video that Bennett recorded showed him walking alongside Pan on a Sacramento street, shoving him from behind and later saying, “So, yeah, I pushed him for laughing, for lying.” Pan stumbled after he was pushed.

Shannan Martinez, a spokeswoman for Pan, said the senator is OK and “will not be deterred.” She blamed years of online abuse by vaccine skeptics against Pan, who authored legislation in 2015 eliminating personal belief exemptions for immunizations, for turning him into a target.

“This extremist movement has been using inciting, violent rhetoric for a long time and it should be no surprise that this is the next outcome,” Martinez said. “It’s very good that (the attacker) didn’t have a weapon.”

Bennett, a Republican, ran as a write-in candidate against Pan in the Democrat’s Sacramento district last year and received 530 votes. He is now pursuing a recall against the senator, who previously fended off another unsuccessful recall attempt.

In the video he streamed live on Facebook, Bennett encountered Pan as he walked around downtown Sacramento.

“What are the chances of this?” Bennett said as he began to follow Pan. “You’ve got to tell us, please, I beseech you, why do you think water is the most dangerous ingredient in vaccines? Now’s your chance.”

Bennett pursued Pan for another block before shoving the senator from behind.

“Yeah, I pushed you! I pushed you. I pushed you. Adios,” Bennett said, as Pan walked away.

Moments later, Bennett said, “I probably shouldn’t have done that.” But he expressed little remorse for actions, adding that if Pan “got what he deserved, he would be hanged for treason for assaulting children, for misrepresenting the truth.”

In a statement, Senate President Pro Tem Toni Atkins, D-San Diego, said, “There is absolutely no reason for resorting to violence.”

“We may not all agree on every piece of legislation, but that is no reason to resort to aggressive and harmful behavior,” she said. “It is shameful that someone would betray the trust we have placed in that process and physically attack Dr. Pan.”

Amid a surge in medical exemptions for childhood vaccinations, Pan, a pediatrician, introduced SB276 in February to give state public health officials approval over exemption requests. Vaccine skeptics decried the bill as a violation of the doctor-patient relationship and have protested for months at the Capitol.

The measure, which awaits a vote in the Assembly and has the support of Gov. Gavin Newsom, would allow state officials to conduct a review if a school has an immunization rate below 95%, the threshold for “community immunity,” or a doctor has granted more than five exemptions in a calendar year. The state could revoke exemptions that it finds are fraudulent or inconsistent with medical guidelines.

Bennett did not respond to a request for an interview. In a second Facebook live video recorded after his arrest, he admitted his guilt and said he would not make an excuse for his behavior. He said he would have to pay a fine and the arrest would go on his record, which is “not necessarily an excellent thing, of course.”

“But I do believe good’s going to come out of it,” Bennett said.

Alexei Koseff is a San Francisco Chronicle staff writer. Email: alexei.koseff@sfchronicle.com Twitter: @akoseff