This is a bad idea. It will raise the cost of campaigns and make it impossible for minor party or independent candidates to win.
http://ballotpedia.org/wiki/index.php/California_Proposition_14,_Top_Two_Primaries_Act_(June_2010)
A California Top Two Primaries Act ballot proposition is on the June 8, 2010 ballot in California as a legislatively-referred constitutional amendment.
If approved by voters, the proposal will require that candidates run in a single primary open to all registered voters, with the top two vote-getters meeting in a runoff. The new system would take effect in the 2012 elections.[1]
http://ballotpedia.org/wiki/index.php/California_Proposition_14,_Top_Two_Primaries_Act_(June_2010)
A California Top Two Primaries Act ballot proposition is on the June 8, 2010 ballot in California as a legislatively-referred constitutional amendment.
If approved by voters, the proposal will require that candidates run in a single primary open to all registered voters, with the top two vote-getters meeting in a runoff. The new system would take effect in the 2012 elections.[1]