May 24, 2016 - This is a question we receive quite often - especially from voters who only vote once every few years. When a voter fills out a registration form, one of the questions asked (in fact it's #14 on the California form) is "Do you want to register with a political party?". There are 8 possible answers, including major and minor parties, as well as declining to affiliate with a party (known as "No Party Preference, or NPP").
But what happens if nothing is selected? Under California law (Elections Code section 2154(b)) states that if "no party preference is shown, it shall be determined that the affiant has declined to disclose a party preference", which means they are categorized as NPP. The voter is sent a Voter Notification Card letting them know that they have been registered as an NPP voter. On the card there are instructions for verifying this information, or how to change the categorization if desired.