Supporters of a proposed ballot initiative to lift, and in some cases eliminate, California's $250,000 cap on noneconomic damages in medical malpractice cases, kicked off their signature-gathering campaign in Sacramento on Monday.

The event marked the start of what could be a five-month-long, multimillion-dollar marathon to gather more than 623,000 valid signatures to put the measure before voters in November 2020.

"We're going to change things because it's the right thing to do," said plaintiffs lawyer Nicholas Rowley, a partner at Carpenter Zuckerman & Rowley who is spearheading the campaign with Santa Monica-based Consumer Watchdog.

The campaign kickoff was held at Frank Fat's, a Sacramento restaurant that was the scene of the so-called napkin deal, a 1987 agreement hashed out among legislative leaders and lobbyists representing lawyers, doctors and the tobacco industry. Spelled out on one of the restaurant's cloth napkins, the deal, among other things, gave plaintiffs lawyers access to higher contingency fees while keeping intact the medical malpractice caps enacted in 1975.

Families of malpractice victims and their political supporters, including former U.S. Sen. Barbara Boxer and Christine Pelosi, chair of the California Democratic Party's women's caucus, railed against the agreement and the cap itself. Gov. Jerry Brown signed the legislation creating the cap during his first year as governor and served as a blockade to any attempt to amend it during his administration's final eight years.

The initiative would tie the noneconomic damages cap to inflation, raising it to $1.2 million in today's dollars and adjusting it annually. Judges and juries would be allowed to award damages above the cap in cases involving "catastrophic" injuries and death. And the measure would bar evidence of collateral sources of victim support, such as insurance policies, and end mandatory periodic payments to plaintiffs.

Initiative backers said they had a scheduled meeting with Anthony Williams, Gov. Gavin Newsom's legislative secretary, Monday afternoon. The governor has not taken a public position on the measure. Rowley said he met with Newsom at a Southern California hotel lounge shortly before he launched his 2018 gubernatorial campaign.

"Gavin Newsom looked me in the eye and said, 'That law is wrong and it's got to change,'" Rowley said Monday. "Hopefully he'll stand up and say that to everybody else."

The governor's press office did not return a message seeking comment on the proposed initiative and Rowley's account of talking with Newsom.

Absent from Monday's event were leaders of the Consumer Attorneys of California, which lobbies for the plaintiffs bar in Sacramento. Organization executives have not taken a position on the initiative and have said previously that the malpractice law should be "corrected" in the Legislature, which returns to session next month.

Rowley said Monday that any legislation solution would have to go beyond simply raising the cap on damages.

A spokesman for Californians Allied for Patient Protection, an organization backed by health care and insurance interests that support of the malpractice cap law, did not return a message left Monday.