Realistically, for Ryan to succeed, he will have to run an error-free race. He will also need to draw a deeply flawed opponent. That seems distinctly possible. The Republican candidates in Ohio are producing the wildest primary in the country, deploying tens of millions of dollars against one another in a competition that has featured bitter insults, accusations of sexism, and a near-physical altercation between two candidates—Josh Mandel and Mike Gibbons—at a public forum in March. Trump’s surprise endorsement of the Hillbilly Elegy author J. D. Vance has created even more uncertainty and infighting in the race as the primary approaches.

Some Democrats have suggested that Mandel, the 44-year-old former state treasurer who lost a 2012 Senate challenge to Brown, would be the best draw for Ryan, who could sharply contrast his willingness to challenge his own party on issues like trade with Mandel’s absolutism, particularly on cultural issues like teaching about race and sexual identity in schools. Mandel’s mask burning and call to eliminate public schools are the types of stunts that rev up partisan ideologues but risk alienating casual voters.

“Most Democrats don’t think Josh can win a statewide election, and there’s a lot of Republicans who feel that way, too,” Gibbons, a businessman who was polling ahead of Mandel and Vance earlier in the race, told me. “He’s a real risk for the party if he ends up the nominee.”…

Ryan’s strategy, according to the campaign aide, who would discuss it only on the condition of anonymity, will be similar regardless of who emerges from Tuesday’s primary: Talk incessantly about creating a manufacturing policy designed to compete with China.