The former president was content to keep a distance for this year’s races for governor. He won’t be so quiet next year — especially if he concludes that a successful midterm is a key step to his restoration to power in 2024. A more visible and vocal Trump has the potential to help Republicans in solid red states but doom them in purple or blue ones. Yet control of the Senate hinges on the results in Nevada, Arizona, Georgia, Wisconsin, Pennsylvania and New Hampshire — states Mr. Trump lost in 2020.

Mr. Youngkin showed that a positive message attuned to middle-class priorities repels Democratic attacks. If Republicans campaign on a unified message that applies conservative principles to inflation, the border, crime, education and health care, they might be able to avoid being tagged as the party of extremism, conspiracy and loyalty to Mr. Trump. Their problem is they have no such message…

Republicans appear either unwilling or unable to treat the former president as a figure from the past whose behavior has done the party more harm than good. They take false comfort in the idea that midterm elections are “thermostatic,” the inevitable repudiation of the governing party that is climatic in nature. They assume they will win next year without doing anything of significance. And they may be right.