I don’t know about you, but when I think of Gore Vidal’s best enemies I conjure up the pugilistic, possibly part-psychotic Norman Mailer and protégé turned critic, Christopher Hitchens. James Graham, however, is interested in Vidal’s on-screen spats with William F. Buckley Jr, the conservative writer and commentator given his own, then innovative debate show, Firing Line. By the time of the 1968 presidential race, Buckley was an established interrogator whose on screen persona evinced high-minded civility. The struggling ABC network recruited him to front their coverage of the main parties’ national conventions, and in a hail Mary attempt to add entertainment to its news coverage and bolster its ratings, partnered him with his ideological nemesis and intellectual match, Vidal.

Watching network executives roam the mocked up director’s booth, vigorously stroking engorged members as the two locked horns, you can see what later troubled Paddy Chayefsky – more heat than light; TV the channel for an unchecked and incendiary stream of consciousness.

The conceit of Graham’s play is that the Vidal/Buckley rivalry was the frontline in 1968 America’s culture war. This is a story with a supporting cast that includes old Buckley debating rival, James Baldwin, and provocateur Andy Warhol. This is the period of counter cultural uprising, of the breaking and rolling back of waves lamented by Hunter S. Thompson – of student protest and political assassination.

America, an uneasy and volatile nation, divided by race and a conflicted sense of self, had, in Vidal and Buckley, poster boys for the opposing factions. As Buckley’s wife helpfully summarises, for ordinary Americans watching these men debate the state of the nation was about which version of the country they wanted to live in – liberal, that is to say something like what we now call progressive, or a country defined by a free market and traditional values. Lucky for us this is such a time capsule and we’ve moved beyond these crude divisions.

All joking aside, and with the contemporary parallels in post-Brexit Britain as sharp as a Vidal bon mot, this is a trip back to an exciting and dangerous time in America, when the fault line Vidal prophesied, was starting to show – old certainties falling through the fissure. Identities were forming as a precursor to what we now call identity politics.

Charles Edwards has Vidal’s ticks and superciliousness down pat; he embodies the aloofness and disdain of the man, while recognising him to be a contrarian of sorts whose arguments pointed to a fundamental contempt for society’s reassuring fictions. The fun casting of David Harewood as Buckley, a theatrical fuck you to the man he plays, works both as a post-modern flag; a sign that Graham et al are very much in Gore’s camp; and a great turn. Harewood conveys Buckley’s arrogance and exasperation at the threat Vidal represents to the essentialist ideals he holds dear, as well his self-doubt as Vidal exposes his latent bigotry and fear of unchecked liberalism.

Graham’s fantasy is that both men ultimately come to the realisation they’re flip sides of the same coin – egos tethered to causes that suit their disposition. What they’re against is as important as what they’re for – a dynamic that shapes today’s non-collegiate, ghettoed politics. The only way forward, the play seems to suggest, is mutual understanding and compromise. A political fairy tale then, but one worth reading to your kids for a couple of hours.