At the June 1972 election, California voters passed Proposition 4. It amended the California Constitution, Article II, section 5, concerning the presidential primary. It has never been altered and is in the Constitution today. It requires the legislature to “provide for partisan elections for presidential candidates…including an open presidential primary whereby the candidates on the ballot are those found by the Secretary of State to be recognized candidates throughout the nation.”
The purpose of this change was to end the requirement that presidential primary candidates must petition to get on the California presidential primary. Before it was adopted, it was very difficult for candidates to get on the California presidential primary ballot; they needed a petition of 1% of that party’s registered voters. After it was adopted, no petitions were needed. The Secretary of State was directed to choose which candidates should be on the ballot by seeing which candidates are mentioned in news media. Many other states copied this idea, and it is in place in almost half the states with presidential primaries.
There is no doubt that Proposition 4 was intended to apply to which candidates are on the ballot, and does not relate to who can vote in the presidential primary. This is clear from the ballot arguments in the Voters Pamphlet, and from the news stories about the campaign for and against the measure. But the California Voters Project has for several years insisted that California is violating its own constitution by holding a semi-closed presidential primary for some parties, and a closed presidential primary for other parties. See this article posted by the Project on May 12.
Representatives of the California Voters Project testified against AB 837 on April 26. AB 837 requires that election officials take steps to inform independent voters of their right to choose the presidential primary ballot of parties that have agreed to let independent voters have such a ballot. The Independent Voters Project witnesses said they oppose AB 837 because the entire California presidential primary is in violation of the California Constitution. They did not acknowledge the legal analysis of the bill, which rebuts their point. And their blog post fails to quote the entire portion of the California Constitution.