Opponents also believe the two rounds of the proposed system would lead to a constant campaign environment, with larger campaign expenditures and increased administration costs for local election officials. Supporters deny that administrative costs will be significantly altered and assert that the "top two" system would produce meaningful elections at both stages.
"You're going to end up with campaigns that are honest, from March to November," said Amanda Fulkerson of Californians for an Open Primary.
They believe the ability of all voters to participate in a single primary will produce general election candidates that better represent the beliefs of the district, producing November contests between two ideologically viable candidates.
"If everybody's going to be the same, why even bother to have the election," countered John Burton, chairman of the California Democratic Party.
He raised the possibility of a fragmented primary electorate resulting in candidates far removed from the ideological center of the district.
"[If] you have nine Democrats running in a highly Democratic district and you have two Republicans running, the two Republicans might end up with more votes than the Democrats," leaving no Democrats on the November ballot in the district.
A study by the nonpartisan Center for Governmental Studies estimated that approximately one third of legislative and Congressional races in California would result in general elections between candidates of the same political party under the "top two" system. It found that those elections would increase campaign spending, but could give a slight advantage to moderate candidates.
"I think voters are hopeful," said Molly Milligan, a senior fellow at the Center and author of the report. "My fear is they might be disappointed when not too much of a change results, because I don't see Prop 14 as a panacea."
If the measure passes, the California Republican Party will implement caucus nominations, with Republican state and county committee members from relevant districts voting to determine the party endorsement for the first round of election. This endorsement would not appear on the ballot, but would limit access to party support and infrastructure to the nominee.
Nehring lamented that the end of party primaries "would reverse an important progressive-era reform which put the power of nominating candidates into the hands of rank-and-file the voters."
Currently, Republican county committees are not allowed to endorse candidates in Republican primaries. California Democrats currently allow primary endorsements if two-thirds of relevant local party committees endorse a candidate.
Some have raised concerns over the lack of a way to replace candidates on the general election ballot under the proposed system. The two candidates with the highest vote totals in the primaries would appear on the November ballot unless one of them were to die, in which case the third-leading primary candidate would take the open spot.
That raises the potential of an election in which a party's candidate wins the primary by a large margin and dies, leaving two candidates from other parties as the only choices on the ballot. Currently, parties can replace their nominees on the ballot in the event of a candidate's death or a major scandal. This would not be an option if Proposition 14 passes.