If either Donald Trump or Carly Fiorina receives the 2016 Republication presidential nomination, it will be a rare achievement. Only once in American history has a major political party granted its prize to someone whose principal qualification was to have served as a corporate chief executive. That was in 1940, when Wendell Willkie was the Republican candidate against President Franklin Roosevelt, who was seeking a third term.

“I’m in business and proud of it,” the 48-year-old Willkie told a Nebraska crowd that spring. “Nobody can make me soft-pedal any fact in my business career. After all, business is our way of life, our achievement, our glory.”

Willkie’s political fate, however, did not ultimately turn on his record as president of the Commonwealth & Southern, a large electric utilities holding company based in New York. In the late 1930s, Willkie’s modest national fame grew mainly out of his public criticism of Roosevelt’s New Deal programs, which he said overregulated industries such as his own.

Born in the small town of Elwood, Ind., the well-read, bighearted, chain-smoking Willkie was a lawyer. Before his promotion to chief executive, he had been the company’s counsel. Until 1939, he had been a registered Democrat; he changed his party affiliation without fanfare. After Willkie made known his intention to run for president, James E. Watson, a Republican and former United States senator from Indiana, warned him that it would be difficult for a party switcher to be nominated. Watson said that in their home state, “It’s all right if the town whore joins the church, but they don’t let her lead the choir the first night.”