He may have put a nail in that coffin with his decision to sign an executive order on Wednesday that would put a halt to the death penalty while he's governor. The state has executed 13 people since the U.S. Supreme Court reinstated the death penalty in 1976.
"Friends and families of the always forgotten VICTIMS are not thrilled, and neither am I!" he added on Twitter.
In 2016 while serving as lieutenant governor, Newsom endorsed a failed California ballot measure that would have repealed the death penalty - an issue so controversial that then-Gov. Scheidegger said that Newsom can grant reprieves to condemned inmates but cannot order the closing of the death chamber or the halting of the effort to find a new lethal injection.
"A study was done a number of years ago in Georgia, which showed that there was a very strong correlation between the race of the victim and discrimination, so that if you were black and your victim was white, you had up to 11 times greater chance of receiving death penalty than the other way around", said Finkelstein.
The state joins Colorado, Oregon, and Pennsylvania, which have similar bans, and 20 states that have abolished the death penalty, it said.
Newsom recently called for more DNA testing in the case of death row inmate Kevin Cooper, who says he was framed in 1983 hatchet and knife killings of four people, including two children, in Chino Hills. In fact, the murder rate in states with the death penalty is consistently higher than in states without it.
California Governor Gavin Newsom
Kent Scheidegger, the legal director of the pro-death penalty Criminal Justice Legal Foundation, said Newsom's order is an abuse of power. Since the 1970s, 79 death row inmates have died of natural causes in the state and 26 by suicide.
"But most of all, the death penalty is absolute, irreversible and irreparable in the event of human error", he continued. In that same election, state voters narrowly approved a measure to speed up death row inmates' executions by limiting their time for appeals to five years.
The third main angle of Newsom's argument is that the death penalty is "costly and burdensome", costing the state $5 billion since 1978. At least 18 of the 25 people who were executed a year ago had significant evidence of mental illness, intellectually damaging brain injuries or chronic childhood trauma or abuse, according to a Death Penalty Information Center report released in December. He also said innocent people have been wrongly convicted and sometimes put to death. However, the death penalty has disproportionately affected people of color and the mentally ill.
But Newsom's action will anger death penalty proponents.
Some supporters of the move pointed out that despite California's status as a blue state, Newsom's decision was a bold one in light of voters' recent support for state-sponsored executions.