Democrats in California have worked hard for years to inflate gasoline prices, but now they’re searching for a fall guy as voters gripe about how much they’re paying to fill up. Round up the usual fossil-fuel suspects!

California Gov. Gavin Newsom on Monday ordered state Attorney General Xavier Becerra to investigate oil companies for allegedly overcharging consumers and price-fixing. Gas prices in California average $4.13 per gallon, about $1.50 more than the rest of the U.S. “The mystery surcharge adds up, especially for...