The California Secretary of State, for well over 100 years, has been publishing official election returns, in a booklet called “Statement of Votes.” These booklets always contain a chart showing historical data on turnout.
These booklets show that California voter turnout is always significantly higher in November general elections, than in primary elections. In the entire history of voter registration in California, over 50% of the registered voters have always turned out for regularly-scheduled general elections.
But no matter what kind of primary election system California has used in past decades, voter turnout in non-presidential primaries is always under 50% of the registered voters. One must go back to 1982 to find any non-presidential California primary election in which at least 50% of the registered voters voted. In June 1982, 52.7% of the registered voters voted.
Even when California used a blanket primary, in 1998, voter turnout in the June 1998 primary was only 42.5% of registered voters. It is true that turnout in the June 1998 primary was better than non-presidential primaries since then. But, California primaries since 1998 have always featured a Governor running for re-election. Generally, turnout in mid-term primaries is higher when there is no incumbent Governor running for re-election. Perhaps turnout in the June 2010 primary will be relatively high, because no incumbent Governor is running for re-election.
Turnout in November elections is always higher than turnout in June primaries because voter interest is always higher in election years in the fall, rather than in the spring. November elections are of heightened public interest, in California and in all states, because the entire nation is voting in November. The drama caused by the fact that all U.S. voters are voting nationwide on the same day, plus the higher stakes in November elections, guarantees that the fall campaign season will always be the high point of voter interest. Proposition 14, shutting all minor party, independent, and non-establishment campaigns out of the fall season, will significantly curtail the circulation of political ideas.