An unusual message will soon hit mailboxes and social media feeds in former Democratic Rep. Katie Hill’s Southern California district: “For once in your life, vote twice!”

The tagline will be featured in mailers and a digital media campaign from Assemblywoman Christy Smith, a Democrat running in the special election to replace Hill in the 25th District. The message underscores concerns that voters may be confused by multiple elections for the same office on the same day, March 3.

There will be two votes: a special election to fill the remainder of Hill’s term; and a regular primary for nominees for the next full term, which starts next January. The two elections are happening on the same day as other California primaries, including the presidential primary.

For the special election primary, a candidate who gets an outright majority will head to Washington. But if no one gets a majority, the top two vote-getters, regardless of party, would advance to a May 12 runoff. That’s what campaign operatives in both parties expect will happen, since 13 candidates are running.

Voters can begin to mail in ballots on Feb. 3, so candidates not only have to compete with the presidential race for attention, they have to educate voters about the unusual elections in a short period of time.