"He has a very good image with Democrats, which is why he's so far ahead," DiCamillo said. "He's very well positioned because Democrats know him and they seem to like him."
Getting known in a state as large as California is no small task. In addition to getting national publicity as mayor of San Francisco when he led the fight for same-sex marriage, Newsom also fixed his name to two high-profile statewide ballot measures last year. Proposition 63 to expand gun control and Proposition 64 to legalize marijuana both easily passed.
DiCamillo said the relatively high support for unknown candidate John Cox was mostly due to his being the only Republican on the list.
A second question, which added potential candidates who have not yet announced, included another Republican, San Diego Mayor Kevin Faulconer. With two Republicans to choose from, voters split right down the middle, with both Cox and Faulconer getting 11 percent support, making them tied for second.
In that larger list, Newsom maintains his lead with 24 percent. Los Angeles Mayor Eric Garcetti attracts support from 9 percent and Antonio Villaraigosa falls to 7 percent.
The rest -- including John Chiang, businessman Tom Steyer and state Senate President Pro Tem Kevin de León followed behind in single digits. Twenty-one percent were undecided.
In California's primary system, the top two finishers go on to face off in November. IGS poll director Mark DiCamillo says the best path for the leading Democrat would be for Republicans to consolidate their support around a single candidate.
"If you’re Newsom, you might be rooting for the Republicans to clear the field," DiCamillo said. "If he’s the Democratic finalist he’s going to want to run against a Republican if he can."
The poll was based on a survey of 1,000 California registered voters. It was administered online by YouGov from March 13-20, 2017 in English and Spanish. Results from the overall sample have a 3.6 percent (plus or minus) margin of error.