Lt. Gov. Gavin Newsom will head the American Civil Liberties Union's new panel studying marijuana legalization in California, with an eye toward drafting a measure for 2016's presidential-year ballot.

"Enough's enough. I can't sit back and support the status quo any longer," Newsom said in a telephone interview Thursday, citing the high prison and police costs associated with marijuana enforcement that disproportionately affects minority communities. "I don't want to be the guy giving the speeches after I'm gone about what we should've and could've done."

Voters in Washington state and Colorado approved legalization measures last year, though California voters rejected one three years ago. The ACLU panel over the next 18 to 24 months will monitor how Washington and Colorado implement their laws, producing research papers and holding forums across the state for the public and policymakers.

Newsom, who said he doesn't smoke marijuana, added that he's unconcerned about any political fallout from taking a stand on the issue.

"To me, it's like smoking anything else -- I want a regulatory regime that doesn't advertise to kids, that doesn't allow public use and secondhand smoke," he said.

Proposition 19, California's legalization measure, was defeated in November 2010 with a 53.5 percent "no" vote. But the ACLU on Thursday rolled out new polling data showing that 65 percent of Californians likely to vote in 2016 support legalizing, regulating and taxing marijuana for adults. Among political affiliations, 74 percent of Democrats and 71 percent of independents support such a measure, while Republicans are split -- 47 percent in support, 50 percent opposed.

Majorities across every region of the state support it, from 73 percent in the Bay Area to 58 percent in the more conservative Inland Empire region of Southern California. Support spans ethnic lines as well: Legalization is supported by 74 percent of African-Americans, 69 percent of whites and 53 percent of Latinos. Majorities of both genders and all age groups support it as well.

The poll of 1,200 likely voters was conducted Sept. 26 through Oct. 6 by Tulchin Research. It had a margin of error of plus or minus 3.1 percentage points.

Newsom said the poll asked about a legalization scheme that included a statewide regulation and taxation, which Proposition 19 lacked. "We owe it to the public to be able to answer as many of those questions as we can before we pass something," he said.

Waiting until 2016, he said, allows time to study the issues while capitalizing on a presidential election's high voter turnout.

One proposed marijuana legalization ballot measure already is circulating for signatures to put it on the November 2014 ballot. And another now awaits its official title and summary before it can start circulating.

Besides Newsom, members of the ACLU panel include Santa Clara County Sheriff Laurie Smith; UC Irvine School of Law Dean Erwin Chermerinsky; Alison Holcomb, who managed Washington state's successful legalization ballot measure in 2012; Denver University law professor Sam Kamin, who serves on a task force implementing Colorado's successful 2012 legalization measure; Keith Humphreys, a former senior policy adviser to the White House Office of National Drug Control Policy who is now at Stanford University; attorneys from drug-policy reform groups; and two past presidents of the California Society of Addiction Medicine.

Josh Richman covers politics. Contact him at 510-208-6428. Follow him at Twitter.com/josh_richman. Read the Political Blotter at IBAbuzz.com/politics.