Any candidate who hopes to be on the November 2020 ballot for Congress or state legislature (which are the only partisan offices on the 2020 ballot other than President) must file by December 6, 2019. This is because the California primary for all office is in March 2020, and the top-two system does not provide any method for a candidate to get on the November ballot except by placing first or second in the primary.

The December 6 deadline is extended a few days for offices in which the incumbent does not file for re-election.

Josh Mahony, the only Democrat who filed to run for U.S. Senate in Arkansas in 2020, withdrew, after the filing deadline had passed. See this story. If the Democratic Party is not permitted to replace him, the only candidates on the November ballot with be the Republican incumbent and the Libertarian nominee. UPDATE: there is also an independent candidate, Dan Whitfield, who expects to collect the needed 10,000 signatures by the May 1 petition deadline. The law does not permit him to start collecting until January 1, 2020, and then he has 90 days to get his signatures.

Here is the brief of the plaintiffs in Boydston v Padilla, a case in State Superior Court in San Bernardino that says California must print up a presidential primary ballot listing all candidates from all parties, and make that available to independent voters.

Here is the government’s brief, defending the existing law. The existing law lets each party decide for itself whether to let independent voters vote in its presidential primary. For both 2016 and 2020, the Democratic, Libertarian, and American Independent Parties are allowing independents; the Republican, Green, and Peace & Freedom Parties are not.

The case has a hearing November 19, Tuesday. UPDATE: Here is the Reply Brief of the plaintiffs, filed November 12.