Opponents claim the proposition actually would reduce voter choices, with only two candidates in the general election. They assert that intraparty general elections would leave little ideological contrast, forcing personality-based campaigns and mudslinging. The single ballot primary, they allege, would strongly favor those candidates with the deepest pockets.
"Literally, it would squeeze voters out of the entire electoral process," Tobin said.
In 1996, Californians voted with Proposition 198 to move from traditional closed primaries to a blanket primary, in which all candidates were placed on one primary ballot and the highest vote-getter from each party moved forward to the general election.
The legality of the system was challenged by the state's political parties on the grounds that allowing all voters to choose party nominees violated the parties' right to assembly. In 2000, the U.S. Supreme Court agreed and ruled the blanket primary unconstitutional in California Democratic Party v. Jones.
Following the decision, California reverted to a modified closed primary system, in which parties can choose whether independent voters will be allowed to vote in party primaries. Both parties have allowed unaffiliated voters to participate in congressional and state primaries, but Republicans have limited presidential primaries to registered Republicans.
In 2004, voters in Washington state approved Initiative 872, which created a "top two" primary system. Unlike the blanket primary, the "primary" round of voting does not force parties to endorse particular candidates as nominees. Under that rationale, the Washington law was upheld by the U.S. Supreme Court in early 2008 and the state's first primary under the system was held later that year.
Other efforts to create "top two" systems have been less successful. California voters rejected Proposition 62 in 2004, which substantively differed from Proposition 14 only in its continued allowance of general election write-in campaigns and some measures assisting minor parties in qualifying for ballot access. Measure 65, a similar initiative in Oregon, failed in 2007.
California's major and minor parties have united against Proposition 14, arguing that it will allow candidates to deceive voters by concealing their true party affiliation and limit voter choice by keeping minor party nominees off of the general election ballot.
"Just like baseball needs teams, democracy needs political parties in order to work. Otherwise you have chaos," California Republican Party chairman Ron Nehring told ABC News.
Minor parties face additional difficulty in that they will not be recognized for registration and candidate party preference purposes unless they meet a requirement of 100,000 registrants. Several of the state's parties do not have this number of registrants and qualify for the ballot by receiving 2 percent of the general election vote for a statewide race in a non-presidential year. That path to recognition would be eliminated by the "top two" system.
Those against the proposition allege that the deal that put the measure on the ballot exemplifies shady backroom politics and assert that the similar primary systems in Washington and Louisiana have led to higher percentages of incumbents being reelected and no significant decrease in partisan polarization.