The only thing that was necessary for the triumph of evil was for a good man to do the ‘right’ thing.

“The Comey Rule”, based on the memoirs of the ex-head of the FBI, James Comey, splits very clearly into two eras: BE, Before the Election – and AE. Detailing the events and investigations which occurred during the run-up to the 2016 US Presidential Election involving investigations into Hilary Clinton’s use of an unsecured email server and the potentially explosive allegations of the notorious Steele dossier.

Like its eponymous…well, ‘hero’ sticks in the throat, so let’s settle on character, the BE period is a little stiff and very dry. Like, really, really dry. A dramatic tinder box just waiting for a spark to ignite and burn everything to the ground. Gleeson is that spark and, in drama as in life, Trump is the catalyst that starts the fire that engulfs everything in flame.

But there’s a lot to get through before Trump – who looms large over everything – actually shows up at the midway point of this three-and-a-half-hour docudrama. It goes to great lengths to ground Comey as the by-the-book, apolitical man of principle, an unbending pillar of red-white-and-blue values whose only allegiance is to truth, justice and the American way. With the benefit of hindsight and the knowledge of the characters involved that it brings, it infuses everything with a pseudo-Shakespearian tragedy of inevitability as the unbendingly principled Comey is presented with an impossible choice regarding the unexpected reopening of the investigation into Hillary Clinton mere days before polling day. Damned if he does, and damned if he doesn’t, his actions are laid bare without overt commendation or condemnation, forcing the audience to consider what they would have chosen to do in his stead.

Surprisingly, perhaps, it’s in the AE era that “The Comey Rule” slightly loses its way. Up until then Jeff Daniels has done a sterling job of embodying the paragon of professional integrity and there’s an undeniable frisson in seeing Comey encounter a man whose morality is diametrically opposed and whose relationship with the truth is estranged at best.

Brendan Gleeson’s Trump isn’t a caricature, like Alec Baldwin’s celebrated “Saturday Night Live” pantomime villain. Gleeson brings a meaner edge to the braggadocio and the intimidation and the obvious intellectual deficiency masked by a soundboard of well-worn adjectives and invectives. The only thing which lets the superb performance down, though, is the hair. Gleeson’s main is far too thick and lustrous to convince as the real thing although it’s expertly coiffured into that ridiculously intricate combover the man has.

It’s here, once the two men meet, that the realpolitik of what would become Trump’s Amerikkka begins and after the dusty formality of the run up to Trump’s surprise victory, you’re waiting for the drama to kick up a gear or two, exploring the post-election manoeuvring and manipulation with the energy, intrigue and elan of “House Of Cards” or even “The West Wing”.

Perhaps it’s the Sergeant Joe Friday-esque “just the facts, ma’am” recollections of Comey himself but where there should be vulgar and venal corruption running amok, the coordinated sycophancy and enabling of those surrounding Trump feels rote and tick-boxy and I’m not sure it ever articulates what “The Comey Rule” actually is.

Perhaps it needed a writer/ director more willing to indulge a little artistic licence and a little less keen to lionise its subject to bring this opening salvo of an astonishing and sustained degradation of the pillars of American civic life to more vivid, visceral life. At its very base, this is the story of an honourable and complacent system based on everyone playing by the rules being completely outfoxed and outmanoeuvred by a group of people playing an entirely different game. Who can tell what Edmund Burke would make of this scenario, where it seems that no matter what the good men and women did, evil triumphed anyway? There are no doubt countless more series and films to come on the tumultuous events of 2016-2020 but this is an underwhelmingly flat foundation for them to build from.