A Nonpartisan Blanket Primary (NPBP) places all candidates on a single ballot and nominates a subset. When using a proportional voting rule, an NPBP always selects candidates representing the ideological span of the voters, rather than simply nominating from parties who may represent a broader range of ideologies. This sets up for a Condorcet general election to elect a strongly-representative candidate.
A nonpartisan blanket primary must elect several candidates when nominating for a single seat—preferably five to seven, and preferably an odd number. When electing only two, the candidates each skew wildly away from overall voter preference—and when faced with a big leap beyond their appetite for change, voters will tend to elect an incumbent or someone closer to incumbent ideology.
A greater number of nominees provides more fine-grained options along the same span of ideology, increasing the likelihood of a highly-representative candidate. An odd count of nominees is also highly-likely to place one in the center of the population’s ideological distribution—a high-consensus candidate.
Voters tend to truncate much-more-frequently after ranking six candidates, and will cluster around their individual ideological centers. Across many voters, this clustering centers on candidates representing ideological portions of the population. A primary involving six times the number of nominees can readily select appropriate candidates for the general election. A top-five, for example, can include over thirty candidates when using Single Transferable Vote.
Because of the high degree of representation and inherent resistance to manipulation of both voting rules, a Meek-STV top-five Nonpartisan Blanket Primary followed by a Tideman’s Alternative Smith general resists all forms of strategic electoral manipulation and propaganda attacks, while reliably representing the whole of the electorate.
For multi-winner elections, the NPBP should pare down to twice the number of seats to fill, and follow up with a second Meek-STV among these candidates to give voters a better chance to rank all of the candidates with likely chance of victory. When electing three from a pool of fifteen, for example, voters are likely to rank few of the ultimate winners, and potentially none, disenfranchising their vote if no primary election occurs.
When there are fewer candidates than planned nominees, that election should not have a primary: the vote rankings would reflect voter choice in exactly the same manner as the general election without any impact on who advances to the general, and ignoring those rankings would constitute a violation of voter trust. Final election should occur at the end of the election cycle with no primary.
In California Democratic Party v. Jones, 2000, the Supreme Court struck down blanket primaries. These primaries put all candidates on one ballot and allowed voters to select one for each seat; the candidates from each party with the highest number of votes advanced to the general election.
The blanket primary enforced an open primary for each seat in the election. This violates freedom of association. By contrast, the Supreme Court found, in Washington State Grange v. Washington State Republican Party et al., 2008, that nonpartisan blanket primaries did not violate freedom of association.
A nonpartisan blanket primary is a State election determining who advances to a general election. As such, none of those nominated are nominated by any party, regardless of their party affiliation. The State doesn’t even give each party a reservation in the general election: if no candidate from a party passes the primary, then no candidate appears on the general election ballot.