As he pushes a proposed ballot initiative cobbled together from gun-control bills that died in the Legislature or on the governor's desk, Lt. Gov.
"Since Sandy Hook, I have sat back as a father and been mesmerized by the inability of the federal government to do anything substantively on gun safety," he said in a recent telephone interview, referring to the 2012 shooting deaths of 26 children and staff at a Connecticut school.
But the expanded background checks and stolen-gun reporting requirements that Newsom seeks to put on the state ballot next fall also fit neatly into an unfolding national effort championed by billionaire and former New York City Mayor Michael R. Bloomberg.
Bloomberg announced last year that he was launching Everytown for Gun Safety, a tax-exempt social welfare organization into which he merged gun-control groups he had formed or funded. He started the new group with $50 million of his own money.
Bloomberg's stated strategy: Confront the gun lobby at the local level, by backing legislative candidates who favor gun control and supporting gun-control initiatives on state ballots, rather than rely on Congress, where the
Campaign finance records show Everytown last year provided more than $4 million to a successful $11 million campaign in Washington state that widened background checks on gun buyers. By contrast, the NRA and its supporters spent less than $600,000.
Additional support for the Washington initiative came from other foundations and a short list of billionaire donors, including more than $1 million from Napster co-founder Sean Parker.
Similar measures proposed this year in Nevada and Maine suggest more of the same.
Campaign finance reports filed in those states show Everytown is providing staff and most of the money for the moves there. The political committee filing the Nevada ballot proposal registered with the secretary of state as an affiliate of Everytown, for example.
The National Rifle Assn. characterizes the state initiatives as an assault by Bloomberg on the 2nd Amendment.
"We want voters to know this is the work of one billionaire," said Amy Hunter, spokeswoman for the NRA's political lobbying arm in Virginia, the Institute for Legislative Action. "We know they are working on the ground to get on the ballot in other states too."
Everytown representatives declined to discuss whether the organization intends to become involved in the proposed California initiative. Neither would Newsom or his political advisors talk about how deeply he plans to tap the Bloomberg vein if his measure is cleared to circulate petitions to place it on California's November 2016 ballot.
But Newsom acknowledges he has met with Bloomberg. He used his Twitter account to thank the former mayor for seeing him seven days after announcing his Safety for All campaign last month.
In the interview, he said he was encouraged to pursue a California initiative by both local gun-control advocates, whom he called "lawyers in the trenches," and "national groups … who feel we need a sustained conversation with the public."
Bloomberg is not Newsom's only connection to the gun-control push in other states.
He was a guest at Parker's wedding and has received campaign donations from the Silicon Valley entrepreneur.
Parker has already contributed the legal maximum to Newsom's 2018 gubernatorial effort and has agreed to provide millions for a Newsom-endorsed initiative, also proposed for next fall's ballot, that would legalize and tax general use of marijuana.
Newsom's proposed gun initiative was written by the Law Center to Prevent Gun Violence, a San Francisco organization that drafts model regulations and defends such measures in court. Tax records provided by the center show it is funded largely by national foundations, including former Arizona Congresswoman Gabby Giffords' Americans for Responsible Solutions.
Ari Freilich, a staff attorney for the center, said much of the group's discussion with Newsom and his political strategists over the summer concerned what to seek from voters in a state that already has strong gun laws.
For the record:
An earlier version of this article misstated the title of attorney Ari Freilich. He is a staff attorney, not legal director, at the Law Center to Prevent Gun Violence.
"But we thought we could do more. California can lead the nation," he said.
Freilich identified nine unsuccessful bills in the Legislature in recent years as the "loose foundation" of the Newsom proposal. He said its central provision — background checks on anyone buying ammunition — was based on legislation championed by Senate leader Kevin de León.
The Los Angeles Democrat has twice won passage of such checks in the Legislature. But he was defeated the first time in 2010 by a successful court challenge to the new law and again two years later by Gov. Jerry Brown, who vetoed a revised version of the proposal, quipping, "Let's keep our powder dry" while legal appeals to restore the first law ran their course.
If Newsom's measure qualifies for next year's ballot, the battle with the NRA is likely to be high profile and expensive.
"The whole country will be watching. The whole world will be watching," said Darry Sragow, a veteran Democratic strategist. "That makes the stakes even higher, and that probably draws even more money."
He said the exposure could greatly benefit Newsom's 2018 gubernatorial run.
"There are a whole lot of Democrats eyeing the governor's race in 2018," Sragow said, "and becoming known to the voters is the single biggest hurdle to that candidacy."