SF and FF are heading for the mother of all contests
The two parties share an intimate knowledge of the difference between being in power and being in office
LEO Varadkar recently claimed that the defining conflict of the next election would be between Fine Gael and Sinn Fein.
It was a clever strategic gambit.
Intriguingly, Fianna Fail leader Micheal Martin is relatively isolated within the party when it comes to recognising this stark reality.
One might have expected a party of ultimate political pragmatists like Fianna Fail to be warier of the rank possibilities offered by Sinn Fein's seductive scent.
However, the intoxicating perfume of possible ministerial office, with Sinn Fein playing the deferential role of junior Coalition partners, can scramble the most acute of political noses.
Whatever about his younger frontbench barons, who are as optimistic as they are ambitious, Micheal Martin and the rest of the veteran Fianna Fail TDs are aware that once the incrementalist Scientologists of Sinn Fein finish digesting the tasty corpse of Labour, they will move on to the bigger game of a still convalescing Fianna Fail.
The war will be an intriguing one, for the theatre of conflict will consist of the working poor – or squeezed middle – who have had the rug pulled from under their feet for seven years to serve the insatiable interests of banks, mandarins and bond-holders.
In the past, these sans-culottes were known as that class who should vote Labour but generally, except for 2011, went with Fianna Fail.
That 2011 Labour triumph is, of course, a narrative which has now essentially ceased, but the borrowed votes have not returned to Fianna Fail.
Instead, in the wake of the strategic decision by Fine Gael to become the party of the insider classes, they are a source of great contention between the two flawed political designs of Fianna Fail and Sinn Fein.
The struggle is rendered all the more intriguing by the reality that, for all of the fuss and flutter, there is little at all that is new about the current threat.
If one wants to understand the prototype for the rise of Sinn Fein, then study the opportunism of Fianna Fail under Charles Haughey in Opposition.
The only thing that matched the intensity of their opposition was the utter absence of credible alternatives. Now as the Coalition, particularly the Labour wing, clucks ever more indignantly at the rise of Sinn Fein, we are watching the same process evolve.
Sinn Fein may be surrounded by the fog of a far darker past but the electorate is more than prepared to take a similar punt.
The conventional political parties have only got themselves to blame for this increasingly dangerous Sinn Fein liaison.
The voter can select only from the less-than-fragrant bouquet of options available to them and, like the Coalition of 1982-'87, the current Government's capacity to command the allegiance of the voters has been hollowed out by its inadequacies.
The rise of Sinn Fein has also been facilitated by the willingness of our political establishment to flirt with the notion of Sinn Fein as 'junior' Coalition partners.
Whilst those who are its advocates think they are political sophisticates, they are, in fact, playing the political equivalent of Russian roulette with a revolver which Sinn Fein has loaded.
Outside of noting that this has played no small role in legitimising Sinn Fein, those who would attempt to seduce the Shinners fail to realise that thE party is interested in power rather than office.
The two may appear to be essentially the same, but a Labour Party that appears to be half in love with political death has discovered all too cruelly that often office is accompanied by a complete absence of power.
By contrast, no party up to today's Sinn Fein has had a more intimate knowledge of the power dynamic than Fianna Fail.
Indeed, when it came to power, such was the purity of the Fianna Fail impulse that it mourned the change whereby the party had to go into coalition with a junior partner, let alone a senior one.
Sinn Fein's equally politically sophisticated knowledge of the difference between power and office means it has no intention of going into Coalition to have done to it what it so vigorously imposed on the SDLP.
It might seem strange that two parties which are so similar are now heading for a great clash.
But as many an Irish murder trial has revealed, brothers, fathers and sons can become the bitterest of enemies when clashing over land or power.
The similarities between the two means, ironically, whether desirable or not, that Fianna Fail is now the sole bulwark against the Sinn Fein absorption by an aspirational class who, in another time, thought Labour but voted Fianna Fail.