Aside from causing Kennedy's then-pregnant wife and 10 children "immeasurable suffering," Newsom said the slaying "also caused great harm to the American people."
It "upended the 1968 presidential election, leaving millions in the United States and beyond mourning the promise of his candidacy," Newsom wrote. "Mr. Sirhan killed Senator Kennedy during a dark season of political assassinations, just nine weeks after Dr. Martin Luther King, Jr.'s murder and four and a half years after the murder of Senator Kennedy's brother, President John F. Kennedy."
He said Sirhan still lacks insight, refuses to accept responsibility and has failed to disclaim violence committed in his name.
"These gaps in Mr. Sirhan's insight have a close nexus to his current risk of inciting further political violence," Newsom wrote.
Robert Kennedy, the U.S. senator from New York, was shot moments after he claimed victory in California's pivotal Democratic presidential primary. Five others were wounded during the assassination at the Ambassador Hotel in Los Angeles. Sirhan will be scheduled for a new parole hearing no later than February 2023. Sirhan will ask a judge to overturn Newsom's denial, said his defense attorney, Angela Berry.
"We fully expect that judicial review of the governor's decision will show that the governor got it wrong," she said.
State law holds that incarcerated people are supposed to be paroled unless they pose a current unreasonable public safety risk, she said, adding that "not an iota of evidence exists to suggest Mr. Sirhan is still a danger to society."
She said the parole process has become politicized and Newsom "chose to overrule his own experts [on the parole board], ignoring the law."
Newsom, a Democrat, is seeking reelection this year after handily defeating an effort last year to recall him in mid-term.
Parole commissioners found Sirhan suitable for release "because of his impressive extensive record of rehabilitation over the last half-century," Berry said. "Since the mid-1980s Mr. Sirhan has consistently been found by prison psychologists and psychiatrists to not pose an unreasonable risk of danger to the public."
During his parole hearing, the white-haired Sirhan called Kennedy "the hope of the world." But he stopped short of taking full responsibility for a shooting he said he doesn't recall because he was drunk.
"It pains me ... the knowledge for such a horrible deed, if I did in fact do that," Sirhan said.
Kennedy's widow, Ethel, and six of his children hailed Newsom's decision in a statement that called RFK a "visionary and champion of justice" whose life "was cut short by an enraged man with a small gun."
"The political passions that motivated this inmate's act still simmer today, and his refusal to admit the truth makes it impossible to conclude that he has overcome the evil that boiled over 53 years ago," they wrote.
The parole panel's recommendation in August to release Sirhan divided the iconic Kennedy family, with two of RFK's sons — Douglas Kennedy and Robert F. Kennedy Jr. — supporting his release.
The panel's decision was based in part on several new California laws that have passed since Sirhan was denied parole in 2016 — the 15th time he'd lost his bid for release.
Commissioners were required to consider that Sirhan committed his crime at a young age, when he was 24; that he now is elderly; and that the Christian Palestinian who immigrated from Jordan had suffered childhood trauma from the conflict in the Middle East.
In addition, Los Angeles County prosecutors didn't object to his parole, following District Attorney George Gascón's policy that prosecutors should not be involved in deciding whether prisoners are ready for release.
The decision had a personal element for Newsom, a fellow Democrat, who displays RFK photos in his official and home offices. One of them is of Kennedy with Newsom's late father. Sirhan originally was sentenced to death, but that sentence was commuted to life in prison when the California Supreme Court briefly outlawed capital punishment in 1972.
