Calvin Coolidge’s vice president, Charles G. Dawes, was a self-taught pianist and composer, and he’s the only vice president to be credited with a number-one pop hit. In 1912, his composition “Melody in A Major,” became a wellknown song for piano and violin. Almost 40 years later, in 1951, a songwriter named Carl Sigman added lyrics to the composition, transforming it into a song called “It’s All …