If you accept what I take to be John J. Miller’s definition of the term “public intellectual”–that is, an intellectual who communicates his ideas to the public at large via the mass media–then Bill Buckley, significant and influential though he has been, has actually had many predecessors, among them H.L. Mencken, who invented what I believe to have been the prototype of the modern op-ed column for the Baltimore Sun in 1911, and G.K. Chesterton, who was doing roughly the same thing for the Illustrated London News as early as 1905. The root of the idea, of course, can be traced all the way back to the periodical essayists of the 18th century (Dr. Johnson, for instance, was a “public intellectual” in something not unlike the modern sense).