The intellectual American subjects of Best of Enemies – bug-eyed National Review editor and conservative iconoclast William F. Buckley Jr; vaguely-aristocratic-looking playwright, screenwriter and very-un-Right Gore Vidal – are a long way from household names nowadays. This documentary covers the infamous ABC debates between the pair, but where I’d expected a “things sure have changed” joint, instead I was presented with a story that very much presaged the modern political and media landscape.

In 1968, your average American still hated intellectuals; unless, of course, they made for good theatre, as did Vidal and Buckley’s televised confrontations, which regularly veered away from issues of the day towards personal attacks and ad hominem point-scoring. The political portrait sketched here is simply a less exaggerated version of today’s landscape, pinpointing the moment that an irreparable rift opened up between the Left and the Right. (Even the era’s inequalities have been exaggerated: Vidal’s complaint about ‘5% of the population having 20% of the wealth’ seems positively quaint in 2015).

Best of Enemies is also a personal story, chronicling the real ramifications of the debates on these two men in their subsequent decades. It’s a consistently illuminating film though, for all the conflict on screen, peculiarly undramatic.