The Season 18 premiere features "Best of Enemies," about the heated debates between conservative William F. Buckley and liberal Gore Vidal that ABC News aired during its coverage of the 1968 Republican and Democratic presidential conventions in an effort to boost its paltry TV ratings. The disdain that the two felt for one another dripped from their every syllable and led the set-tos to become personal. The result: must-watch TV; and the dawn of the modern age of contentious public discourse.