The irony that the decision to exclude God was taken on May 29th - Trinity Sunday - was lost on the delegates, until, in his review of the papers on RTÉ the following morning, veteran journalist PP O’Reilly drew attention to it.

The result was that, just four days later — in what Sean O’Rourke, the then political correspondent of the Irish Press, called “the quickest U-turn in recent Irish political history” — PD leader Des O’Malley announced that God would after all get a mention in the preamble to the new Constitution it was proposing.

In truth, there was nothing startlingly novel about a proposal for a ‘godless’ Constitution, a secular document. In May, 1972, the report of a working party established by the Irish Theological Association (to examine provisions in the Constitution which might be considered discriminatory or divisive on religious grounds) recommended a secular preamble.

“It is customary for a Constitution to have a preamble,” it reported. “Whatever its interpretative value or legal significance, it creates a certain social and psychological climate.

“The working party recognised that the present preamble reflects the predominant religious strand in the Irish tradition, but it is not satisfied that this is necessary or appropriate in such a legal document. And the preamble may well create a climate unacceptable to some Irish citizens.”

If this latter observation applied in 1972, then it has much greater relevance today, when census figures show that there has been a significant increase in the number of Irish people ticking the ‘no religion’ box on census forms.

The 1972 ITA working party consisted of the six following members: Rev Enda McDonagh, professor of moral theology in St Patrick’s College, Maynooth; T.C. Kingsmill Moore, former judge of the Supreme Court; Sean MacBride, SC, former minister for external affairs; G.B.G. McConnell, Presbyterian minister, former convener of the General Assembly’s Committee on National and International Problems; Louis McRedmond, former editor of the Irish Independent and lecturer in journalism, College of Commerce, Rathmines; and Mary Robinson, senator and professor of constitutional and criminal Law in Trinity College, Dublin.

The Ireland they were writing in and about was very different to the Ireland of 1937, when Éamon de Valera put a constitution (Bunreacht na hEireann) before the Irish people, in a referendum, to replace the 1922 Free State Constitution.

One might not wish to fully endorse the claim, made earlier this year by Pat Rabbitte (in an article on the Kerry Babies case in the Sunday Business Post), that the Ireland which produced Bunreacht na hEireann was really “a theocratic State”, in order to appreciate the extent to which legislators deferred to the Catholic Church.

The de Valera papers have revealed how importantly the then taoiseach viewed the preliminary approval of Pope Pius XI for the new Constitution, before it was even submitted to the Dail and the people.

On April 16th, 1937, he sent the secretary of the Department of External Affairs (now Foreign Affairs), Joe Walshe, on a secret mission to the Vatican to see the Pope, “with a view to obtaining, confidentially, his approval and blessing, before the draft Constitution is published”.

Walshe had a series of meetings with the secretary of state, Cardinal Eugenio Pacelli (the future Pope Pius XII).

Despite the “special recognition” given to the Catholic Church in Article 44 (bearing out Pat Rabbitte’s contention that John Charles McQuaid, the future Archbishop of Dublin, was “the principal influence on Éamon de Valera, when the 1937 Constitution was being prepared”), Pacelli said the recognition given to other Christian Churches in the same article “nullified any advantage which might have derived from exclusive recognition”.

After several days of meetings, Walshe was greatly disappointed when he received the formal response of Pius XI: “I do not approve; neither do I disapprove. I shall maintain silence.”

But even if formal Vatican approval was not forthcoming in advance — the referendum was held on July 1, 1937 — there was no doubt that, in the words of John A Murphy, emeritus professor of Irish history in UCC, the 1937 Constitution had “a distinctly Catholic flavour”.

When the 1937 text was published, many women’s groups were aggrieved and angry, and afterwards boycotted the referendum. They complained that Article 41 reflected the prejudices of a patriarchal society and was intended to convey that a “woman’s place was in the home” (which is more or less what a sub-section of this article says).

As the draft was being finalised, Dr McQuaid wrote: “The feminists are getting angry and moving into action. They seem stung by the suggestion that the normal place for a woman is in the home.”

Producing a new Constitution today would involve a very different process and would yield very different results. The political mix is very different today, and new uncertainties abound. And given the possible political permutations that may emerge from Brexit, the need to plan for, and to accommodate, a united Ireland has taken on a new urgency.

In the Irish Press in July 1987 — on the 50th anniversary of the referendum to adopt the 1937 Constitution — former taoiseach Garret Fitzgerald wrote that the “enactment of a third Constitution (following on from the 1922 and 1937 documents) to provide a basic law more appropriate to modern Ireland is one that will have to be faced in time”.

That time is closer to hand now than ever before. We don’t know what the political and socio-economic mix post-Brexit will be like. Will there even be a Brexit?

In Britain, political heavyweights such as Tony Blair and Michael Heseltine believe there will be another referendum on Britain’s future, vis-à-vis the EU.

And some commentators — notably Brendan O’Leary, professor of political science at the University of Pennsylvania (he was political adviser during the making of the Belfast Agreement) — are now talking about not just Brexit, but also UKExit, “which is to say the departure of the whole of the United Kingdom, rather than of just Great Britain, from the European Union”.

Prof O’Leary predicts that there will be another referendum on Scotland’s independence, and likely before a referendum on Irish reunification.

“Differently put, the union of England, Scotland, and Wales may break up first,” he says.

And if we have a referendum on Irish reunification? Again, the scenario is very different to what it was 50 or 60 years ago.

“The old unionist case against reunification had three major components: an independent Ireland meant Rome rule; the Republic was monocultural, and unattractive, compared to the multinational UK; and the Republic was poorer, pursuing an isolationist and irrational economic policy,” Prof O’Leary wrote in Ireland 1916-2016: The Promise and Challenge of National Sovereignty.

Whatever their past truth, these arguments no longer pass muster. Ireland is de-Catholicising, and it is multicutural and prosperous — multicultural because it is prosperous, and vice versa.

“It is richer than Northern Ireland, absolutely and per capita, before and after the subvention by the UK treasury is added to the North’s ledger. And sovereign Ireland is staying in the world’s largest market, which all gravity-weighted models of international trade suggest is the wiser bet.”

But, of course, as he admits, unfolding events confirm that no one knows the political future. But if we do move, as Dr Garret Fitzgerald said, in 1987, to a third Constitution, we can predict that it will be a secular document. But a secular Constitution in a secular State does not necessarily mean a secular society.

Ireland is undoubtedly “de-Catholicising”, as Prof O’Leary says. But while that will have real implications for the institutional Church, it doesn’t necessarily mean religion is going to disappear to the margins.

And there is no desire (except among militant atheists) to exclude religion or religious voices from the public square.

A modern State may seek to ground its legitimacy in democratic authorisation, rather than by reference to religious sources or divinely appointed authorities.

That doesn’t mean the same State will actively engage in promoting secularisation, pushing for the decline of

religion, both in society and in the minds of individuals.

On the contrary, the modern State will work to provide space for religion, support religious liberty, and advocate respect for religious voices.

That is a true mark of pluralism. Bearing that in mind is going to become more and more important as we head into a future characterised by socio-political and constitutional uncertainties.