Aged 16, I got my break in the theatre. Playing a broom carrier in the school production of Macbeth, I arrived for the performance to find myself promoted. A classmate had fallen ill.

My new role was that of the Captain in the second scene: gravely wounded from battle, he reports to King Duncan how bravely Macbeth has fought. For a tortured hour, I frantically paced the school corridors, feverishly trying to learn my newly acquired lines.

When my moment came, I stumbled on stage, convincingly dazed. “Doubtful it stood,” I intoned, without the first idea of what I was talking about, and promptly forgot the entire remainder of my short speech.
There was a dramatic pause, and one of actors hissed at me: “your wounds!” In a flash of inspiration, I bent double and howled in pain, while our director whispered the next line to me from offstage.

Twelve lines later, all interspersed with groans of extraordinary ferocity and length, I staggered off, in the first stages of post-traumatic shock. It was likely one of the most prolonged and pronounced performances of the Captain in stage history.

It was only recently, rereading the play 20 years later in advance of the Abbey’s new production, that I realised the full significance of the Captain’s role. Reporting from the battlefield on Macbeth’s defeat of “the merciless Macdonald”, the Captain describes how Macbeth “unseamed him from the nave to the chops, and fixed his head upon our battlements.”

“O valiant cousin!” replies the King, “worthy gentleman!”

This, then, is to be our hero: a man whose great glory is to have cut another open from navel to chin.

Shakespeare’s other great hero, Hamlet, is introduced to us as having just returned from university; Macbeth is introduced freshly bloodied from the battlefield. Hamlet, tasked with the pursuit of a just revenge, prevaricates and philosophises; Macbeth, in thrall to a demonic prediction, sets quickly about power-seeking carnage.

Hamlet belatedly realises “the readiness is all” and commits to action. Macbeth’s similar moment comes when he resolves to ever more decisive brutality, deciding to have Macduff’s wife and children killed: “be it thought and done,” he says.

Macbeth, thus, is the antithesis of Hamlet. But he is no less empathetic for it.

If Hamlet is the prince that all men would rationally wish to be, Macbeth is the man that they dream, and fear, they are.  (The critic Harold Bloom elaborates on this in his great book on Shakespeare, The Invention of the Human.)

Macbeth is no amoral villain: he has an innate sense of decency (“I dare do all that may become a man; Who dares do more, is none”) and a deep awareness of the ills he has inflicted on others, and on his soul. “My soul is too much charged with blood of thine already,” he tells the vengeful Macduff. And yet his lust for blood and power overturns his moral order.

Though Macbeth craves power, he barely knows to what end. Having seized it, he is tormented, until the mounting threat to his reign forces him back into direct action. It is, perversely, in the embrace of violence that Macbeth is most at peace, and most authentic.

This authenticity is rivetting. It is what animates every great war movie, and every great sporting encounter. Anyone who has ever lost themselves in the moment of a contact sport knows that there is little that feels truer; and yet the line between such fulfilling immersion and overwhelming aggression is a frighteningly fine one.

Around this character, the play Macbeth moves with the relentless urgency (it is half the length of Hamlet) of a thriller, under the spell of the witches’ riddle that Macbeth will be killed by “no man that’s born of woman”.

Its politics is, at a bloodier level, the politics revealed by Pat Leahy’s recent portrait of Fianna Fáil in government, Showtime, and Andrew Rawnsley’s of New Labour in The End of the Party.

“No Irish political party – and few in the world – is as singularly devoted to the acquisition and retention of power as Fianna Fáil,” writes Leahy. “They will do anything and say anything and promise anything and, in the end, concede anything to secure it.”

Reviewing Rawnsley’s book in these pages last week, Ruairi Quinn wrote how Gordon Brown “sees conspiracy and treachery all around him.”

“The brilliance of the public face of New Labour’s triumphant three election victories obscures intrigue, vicious back stabbing and unbridled envy,” he wrote.

Commentators often lament that the media reports on politics as if it were sport, a clash of the ash rather than a clash of ideas. But what Shakespeare recognises is that the pursuit and defence of power is both a primal tendency and a gripping – and ennobling – spectator sport.

Fashionable as it currently is to call for a “new politics” in Ireland, we will always thrill, like King Duncan, to the prospect of a warrior in battle.

The external conflict in Macbeth is one between the forces of ruthless pragmatism – epitomised in the Macbeths – and between those of more principled authority, represented by Malcolm’s rightful claim on the throne.

But the unspoken truth is that even Malcolm’s principles will likely be usurped by power. The witches, after all, predict that the lowly Banquo, not the new king, Malcolm, will beget kings, foreshadowing future bloody battles in Macbeth’s aftermath.

The only difference between Macbeth’s politics and ours is that Macbeth takes backstabbing more literally.

Booking on www.abbeytheatre.ie and (01) 87 87 222.

Published in the Irish Independent.