Douglas Holtz-Eakin, an economist and president of the American Action Forum, a conservative group, said those results were hardly surprising. Trade has never been an easy sell to the public, he said, because the costs, in shuttered plants and lost jobs, are large and obvious, while the benefits — lower consumer prices and greater productivity — are diffuse and hard to see.

“You have to make the case on a regular basis that the benefits are greater than the costs,” Mr. Holtz-Eakin said.

Mr. Holtz-Eakin, who has endorsed Mr. Kane, said the Republican Party needed candidates who would make the case for policies that are more popular with economists than with the general public, among them immigration, fiscal restraint and trade.

“Campaigns are teachable moments in the United States,” Mr. Holtz-Eakin said.

If any district in Ohio is likely to be receptive to Mr. Kane’s economics lessons, it is the 12th. The district — which went for Mr. Trump by about 10 points in 2016 — includes rural areas, but the bulk of the population lives in relatively affluent, educated Columbus suburbs that have largely escaped the postindustrial decline that has afflicted Youngstown, Dayton and other cities. Dublin, where Mr. Kane moved late last year, is one of the state’s wealthiest cities, with a median household income of more than $125,000.

Campaigning on a recent Monday, Mr. Kane did not try to run away from his more contentious positions, or from his wonkish résumé. At a meet-and-greet with voters at a French bakery in Dublin’s quaint downtown, Mr. Kane broke the ice with stories about his days at the Air Force Academy, but quickly pivoted to citing articles he had written promoting free trade and entrepreneurship.

Even on friendly turf, however, Mr. Kane faced some skepticism. When one attendee, Caroline Lahrmann, asked about immigration, Mr. Kane noted that he had written 20 articles and was working on a book about the subject. Then he moved into an intricate discussion of immigration policy: why immigration is important for the economy and why he supports work permits, but not a pathway to citizenship, for people in the country illegally.