It'll be closer to 35% because California is moving towards the Democrats. Yes, a 20% shift in one year is enormous and unrealistic to expect but it shouldn't be ignored. A 5% shift would be worth looking at but a 20% shift is meaningful. The general election was even more one-sided for Hillary Clinton than the 2012 election was for Barack Obama due to Donald Trump's unpopularity. And 2018 should be a Democratic year. If California voters were anti-Trump in 2016 they'll be even more anti-Trump in 2018.
It'll be closer to 15% because the 2016 primary turnout was skewed heavily Democratic due to there being a competitive Democratic Presidential primary and an uncompetitive one. It was an anomaly that can't be duplicated. Mid-term turnout is always lower and there are a lot of people who'll stay home because Clinton and Sanders won't be on the ballot. Yes, Hillary Clinton won the general election by 30%, but that was because people disliked Donald Trump. There were 14 districts where Republicans won the congressional race and another 6 where they got between 42 and 49% of the congressional vote. Hillary Clinton won those 20 districts by 3%, but congressional Republicans won them by 10%. Based on the congressional margin the November electorate was really Democrats by 17%, not 30%.
This is important because if the gubernatorial primary is 55%D-40%R Democrats are unlikely to take both spots in top two, but if it's 64%D-29%R that becomes a lot more likely. Harris and Sanchez did take 92% of the Democratic vote in 2016. With the presence of John Chiang and Delaine Eastin in the race that number should be lower.
Gavin Newsom has positioned himself as the progressive in the race. He’s running on no moderation at all. Republicans are irrelevant in the state. We’re going for a progressive paradise! Whether Newsom is in fact on the that far left isn’t relevant. He’s selling himself there. And it’s not a bad place to be in a Democratic primary. He will get more Democratic votes than Villaraigosa and then would crush a Republican in the general election.
Villaraigosa is positioning himself as the level headed pro-business candidate. He’s a big charter schools advocate and has run afoul of the CTA. He called single payer unaffordable, running afoul of the California Nurses. Those are two of the most powerful unions in the state. Running to the right of Newsom is a tough spot to make top two from but Villaraigosa really has no other choice. He can’t get to Newsom’s left.
While Newsom is hoping that strong Republican turnout will give him a Republican opponent, Villaraigosa is hoping a divided Republican field gives a result like 2016. If the two of them make top two Newsom could be in trouble. Villaraigosa would be positioned on the left of 50%+1 while Newsom would be to the left of that. Newsom would need to pivot to the center to win Republican and independent votes but that’d betray progressives. If Villaraigosa has run a strong campaign he’d already be well positioned.
That brings up the question of how Villaraigosa could win being to the right of Newsom when Loretta Sanchez didn't. There are a few reasons. First, money. Sanchez didn't have much while Villaraigosa has quite a bit. He'll need a lot if he's going to try to position himself in a sweet spot of not conservative but not too liberal. Newsom's positioning is far easier. He can just recite the progressive positions. Sanchez had trouble positioning herself in the right spot. She really didn't have moderate positions on anything other than defense and her congressional track record wasn't strong. She was just a less desirable version of Kamala Harris. Finally, the offices are different. While people tend to vote ideology for the House and Senate they are more likely to vote competence for governor. Of course Villaraigosa will have to show he's more competent.