The race for state schools chief in California is typically a sleepy affair, but not this year.
The nonpartisan election has become a multi-million dollar proxy fight for the growing tensions between California's teachers unions and reformers seeking more accountability.
In a twist, the leading candidates in Tuesday's primary are both Democrats. Incumbent Tom Torlakson, a former state lawmaker, is supported by the unions and the California Democratic Party.
His main challenger, Marshall Tuck, is a former charter school executive who has the backing of most of California's major newspapers and reform-minded Democrats such as former Los Angeles Mayor Antonio Villaraigosa.
Both support the Common Core State Standards, but Tuck wants to reform the rules that base layoffs on seniority and make student test scores a factor in teacher evaluations.