Official Title: Redistricting. State Senate Districts. Referendum.
For decades the politicians in the state legislature wrote their own tickets on California legislative districts, and also for the U.S. Congress districts in the state. The results were a disaster. It was almost impossible to defeat an incumbent in an election. Almost all districts were either heavily Democratic Party or Republican Party dominated. In order to achieve this, the Democrats in the legislature gave up roughly 3 seats in U.S. Congress.
In 2008 and 2010 the voters approved Proposition 11 and Proposition 20, setting up an independent commission to draw district boundaries without respect to the needs of individual politicians.
Republican Party politicians did not like the results of redistricting. They put Proposition 40 on the ballot. A Yes votes approves the new districts (really just State Senate districts) while a No vote allows the California Supreme Court to appoint former judges to redo the redistricting.
Meanwhile the California Supreme Court has ruled that the State Senate districts under consideration will apply in this 2012 election. Proposition 40, in effect, needed to be on the primary ballot to be effective; being delayed, it now borders on the ridiculous.
Yes on 40, up hold the independent redistricting commission.
Proposition 40 summary, official arguments, and text