Ohio Senator Sherrod Brown, a Democrat, is seeking a third term in 2018. His main Republican challenger at this point is Josh Mandel, the state treasurer, who ran a losing campaign against Brown in 2012. But Republicans in the state are leery of Mandel’s retread bid, particularly in a year that could be difficult for the GOP. Mandel’s reputation has been dented by scandals and inflammatory statements, such as when the candidate, who is Jewish, blasted the Anti-Defamation League for criticizing figures it associated with the white nationalist “alt-right” movement.

Vance had been working for the Trump-supporting Silicon Valley venture capitalist Peter Thiel before moving to Columbus, Ohio, earlier this year to found a nonprofit. “It was an effort to do something with the momentum I had from the book and start thinking about solutions,” he said. His interest in policy issues led him to Jai Chabria, a former political adviser to Ohio Governor John Kasich, who helped introduce him to local and national political players and donors.

Vance said he began to seriously consider becoming a candidate when he saw the way his message resonated with both the elite and grass roots of the GOP. “I’m a conservative, but I think the party has really lost touch with working- and middle-class Americans,” he told me. In speeches to groups as varied as the Allen & Co. conference in Sun Valley, Idaho, and the Lucas County Republican Party, in Toledo, “this thunderous critique of Republicans for being the party of the rich was surprisingly getting a lot of applause, even in rooms full of rich people. That made me think I should take [running] more seriously.”

Chabria, the political consultant, said audiences were “spellbound” by the combination of Vance’s timely message and personal charisma, even though many had no idea who he was. “I haven’t seen a reaction like that, to someone that people didn’t know, ever,” he said.

Local and national donors expressed enthusiasm. Vance commissioned a poll that tested his viability in the Republican primaries for both governor and Senate. He was particularly concerned that his opposition to Trump would turn off base GOP voters. But the poll led him to conclude that that would not pose a significant problem and that he would be a viable candidate, particularly in the Senate race. “Based on the polling we had done and the backing we had, it was very clear that J.D. would have been the Republican nominee,” a person familiar with Vance’s decision told me.

A Vance candidacy would have posed an intriguing test of a new sort of Republican populism, one that combined Trump’s critique of the GOP elite with the reformist vision of conservative thinkers like Yuval Levin (and without Trump’s divisive rhetoric). In a recent New York Times op-ed, Vance argued that Republicans must be willing to financially support Americans who would lose their health insurance in a repeal or reform of Obamacare.