The Derry Diocesan Catechism used to deal with one of the core concepts of Christianity in call-and-response form. We'd sing it out in Sister Xavier's class at St Eugene's Infants'.
How many persons are there in God? There are three persons in God. Are there then three Gods? No, there is but one God. How is this explained? It is a mystery. I used to think that was marvellous.
Here's a secular example of the same phenomenon.
How many parties are there in Sinn Fein? There are two parties in Sinn Fein. Are there then two Sinn Feins? No, there is but one Sinn Fein. How is this explained? By reference to different strategies for winning votes.
Consider. Young Killian Forde has just done a runner from Sinn Fein in Dublin. The party says it was too Left-wing for him.
As chair of Dublin City Council's finance committee, he had, on December 21 last, proposed a budget which included the removal of a waiver on bin charges for the poorest section of society. Low-income families will now have to pay â‚¬206 a year to have their bins emptied.
That went against the party line, which resulted in the rift which led Killian last week to join the Labour Party. The development sparked an exchange of verbal hostilities over whether he should have resigned his seat and the differences between the parties which the bin charges issue exemplified.
Bitter mention was made of Labour's support for the privatisation of Aer Lingus. In contrast, Sinn Fein had brought Gerry Adams to Dublin to stand at the airport with a placard, 'Save our National airline - No Privatisation'.
A stickler for socialist principle might suggest that Sinn Fein's Leftism in the South hasn't been entirely consistent. Councillors in other areas - Sligo, Waterford, Leitrim - have voted through budget estimates which included household charges.
Nevertheless, although you don't have to be ablaze with revolutionary fervour to find yourself on the far side of Eamon Gilmore, the party in the South is entitled to be regarded as centre-Left.
Compare the Dublin brouhaha, though, with the resignation from Sinn Fein of Fermanagh councillor Domhnall O Cobhthaigh (below) in September last year in order to join the Socialist Party. He explained he could no longer remain in a party which, at Stormont, was "implementing cuts, job losses and privatising public services".
It's argued by Sinn Fein members that it has no option here but to go along with economic policies which it finds distasteful so as not to endanger power-sharing with the DUP. But this won't really do.
There wasn't an Executive to save back in September 2006, but a mere Preparation for Government Committee, to which each of the parties submitted its vision statement for the economy.
The DUP said: "Northern Ireland needs a serious dose of introspection within its government department's [sic] vis-a-vis their relationship with the business community and the promotion of a genuine partnership between government and business, with government taking on the role of facilitating entrepreneurial opportunity."
Sinn Fein said: "We should say yes to goal-driven tax incentives which increase R&D activity, aid new product and process innovation, enhance worker training and development, help our entrepreneurs break into new markets and aid environmental improvements."
Each statement sat easily enough with the other. The common approach was evident in transport proposals from DRD Minister Conor Murphy in November.
At the moment, Ulsterbus, Metro and Northern Ireland Railways are within the public sector, under Translink. Now it's proposed "to move towards a performance-based contracting regime with Translink and other operators, [providing] opportunities for private operators to identify potential gaps in the market and to apply for a permit to deliver services on those routes".
Translink would bid for contracts for routes against the private companies. All would enjoy equal access to stations built with public money, as well as to bus stops and travel information.
Consultants FGS McClure Watters, hired by the minister in 2008, advise that Translink should try "to enter the new environment as a leaner operator, and avoid entrenching any current inefficiencies in terms of working practices".
Wages should be cut - Ulsterbus salary costs by 11%, Metro wages by 5.5%. Jobs would go - 236 support staff in Ulsterbus, for example. These changes follow the pattern of piece-by-piece privatisation of public transport in Britain.
On this evidence, corroborated across other departments, Sinn Fein in the North is not a party of the Left which has reluctantly gone along with policies it finds repugnant, but is a party of the centre-Right. Which of the economic measures it has initiated or implemented in its time in government would be reversed by the Tories under direct rule? Sinn Fein in the South veered to the Left in search of electoral support to lift it into coalition with Fianna Fail. The objective was to win a share of government across the island.
If this meant showing a Left face in the South and taking a Right stance in the North, so be it.
Is Sinn Fein, then, a party of the Left or a party of the Right? Neither. It is a nationalist party, doing what nationalist parties do.
Anyone looking for a vehicle for specifically working-class advance, North or South, will have to look in a different direction.