A biography some years ago described Bruce Barton
https://en.wikipedia.org/wiki/Bruce_Fairchild_Barton as *The Man Everybody Knew.* The title was of course a take-off on Barton's 1925 best-seller *The Man Nobody Knows* which portrayed Jesus as the greatest advertising man of all time. A *Time* article in 1940 summarized the career of the founder of Baten, Barton, Durstine & Osborn (BBDO) as follows:
"Redhaired, blue-eyed Bruce Barton, 54-year-old advertising tycoon, made millions selling Americans on reading (Dr. Eliot's Five-Foot Shelf); on clean collars (Cluett-Peabody collar ads); on shaving (Gillette); on working (Alexander Hamilton Institute); on Jesus and the Bible (The Man Nobody Knows, The Book Nobody Knows). Barton, a born preacher and sloganeer, a superb luncheon-club speaker, son of a Tennessee clergyman, implemented his creed of service by fighting his way into Congress in 1938 [actually Barton first won election to Congress in a special election in 1937--DT] as an amateur from Manhattan's only Republican district--the Silk-Stocking Seventeenth, compounded of Park Avenue and nearby slums." (October 7, 1940 article--now available online only to subscribers)
Anyway, as the article indicates, Barton ran as GOP candidate for the US Senate from New York in 1940, at Willkie's urging. He lost to incumbent Democratic senator James Mead by 53.3% to 46.7%
http://en.wikipedia.org/wiki/United_States_Senate_elections,_1940
Suppose Barton had upset Mead? This may seem unlikely, given that Mead ran ahead of FDR in New York, but let's say there's some scandal involving Mead. (It might also help if FDR had not delivered his famous cadenced denunciation of "Martin, Barton, and Fish.") Does he then become a plausible presidential candidate for the GOP? Conservatives might like the fact that here was a conservative who knew something about mass communication--much more than, say, Taft did--and who could also challenge Dewey in his own New York base.
To be sure, Democrats would complain about Madison Avenue taking over the GOP and trying to sell the party like soap with slick ads, etc. (Of course they said that in OTL anyway.) But I am not sure to what extent most voters shared liberal intellectuals' hostility to advertising, and I would not assume that an advertising man could not be elected president--after all, it was once thought that no actor could ever be taken seriously enough to be elected to that office...