Democrats think Mr. Trump is the gift that keeps on giving. They ran against him in 2018 and took the House, in 2020 and took the White House, and in January 2021 in Georgia and regained the Senate majority. They did it again in California, and they’re also running against Mr. Trump in the Virginia Governor’s race this year.

They figure, with ample evidence, that Mr. Trump won’t be able to resist injecting himself into the center of the 2022 campaign, demanding in particular that all GOP candidates claim the 2020 election was stolen. Democrats will use the former President as their favorite get-out-the-vote foil, and the media will pretend 2022 is a dry run for Mr. Trump’s revenge campaign in 2024.

The California rout ought to cause some hard Republican thinking about a 2022 message. They can’t win suburban seats running solely against vaccine and mask mandates. They also can’t win by joining Mr. Trump’s “I was robbed in 2020” tour. They need to make the case against the Biden-Nancy Pelosi agenda and offer their own ideas for the future.