Rummaging in the garden shed recently, I came across a small dusty, rusted, fold-up stool that must have belonged to previous owners of our house. The seat is a gaudy, rainbow-striped sheet of nylon, the legs hollow tubes of cheap aluminium. And yet it is in its own way a historic object. It speaks as directly of a certain time and place as any relic in the National Museum.
As soon as I picked it up, I could think only of the events of 20 years ago this month, when, for the first and only time, a Pope visited Ireland. These little fold-up chairs, easily carried to the Phoenix Park, to Limerick Racecourse, to the hilltops around Knock, to Galway and to Drogheda, were so redolent of those events that they were universally known as "papal chairs".
And now, as they gather dust and rust in the garden sheds of Ireland, they are, astonishingly, all that remains of what seemed at the time to be an epoch-making event. You don't t have to be a secular sceptic to be struck by the extraordinary contrast between the rhetoric of September 1979 and the reality of September 1999.
Even though we have lived through what amounts to a social revolution in the Republic in the last 20 years, it is still hard to grasp quite how unimaginable it was in 1979 that the papal visit would have no lasting effect whatsoever. For church activists, the anniversary can bring only bleak reflections.
In the current issue of the Redemptorist magazine Reality, the editor, Father Gerard Moloney, sums up the sense of regret among Catholics. The "long-term impact" of the papal visit, he writes, has been "negligible".
"Today, it is scarcely felt at all. Rather than consolidate and renew traditional Catholic values and loyalties as church leaders hoped, more and more Catholics - even many who are regular Mass-goers - have chosen to go their own way and make their own moral decisions with little reference to what the church has to say.
"The Pope's views on contraception and on family life, for instance, which he made abundantly clear during his visit, have simply been ignored by many. Mass attendance and religious adherence have continued to decline. Indeed, in some urban areas, and among younger Catholics, they are now in free-fall. The boost in vocations that followed the papal visit proved to be only a temporary little blip."
In the same magazine, Fintan Deere and Steve Dempsey report on the perceptions of true believers who took part in the huge papal events. They have no illusions. They say things like "not as many people would go today" and " things have changed".
Anne McElheron, who sang in the choir at the papal Mass in Phoenix Park, notes that, if the Pope came again, she would expect to see fewer young people in the crowd and to encounter protests.
Even her own attendance would be equivocal: "I would go to see him if he came again, but out of sympathy. I have many reservations about the church, about their attitude to women." And these, remember, are the faithful. Beyond them, there are the growing legions of the indifferent and the actively hostile.
For the church leadership and for conservative lay Catholics, there is a convenient explanation for what is, from their point of view, a terrible turn of events. In their view of the world, a coherent, stable Catholic consensus could have been preserved were it not for the machinations of secular liberals and in particular of the media.
Yet one of the significant things about the impact - or rather lack of impact - of the papal visit is that it gives the lie to this notion. For the fact is that 20 years ago this month, the church had everything it could possibly dream of: a completely compliant State, an utterly pious media, a triumphal fusion of church and nation into one apparently indissoluble mass.
It is hard for anyone who wasn't around at the time to imagine how completely the papal visit overwhelmed all critical thought and sidelined any notion of dissent. For the State, the visit was, in the words of Michael O'Kennedy, then minister for foreign affairs, "the Government's first priority". This was not the arrival of a great foreign dignitary, it was a sacred moment. As O'Kennedy puts it in Reality: "there was a deep sense that of all the Irish who had suffered for their faith, we were the generation privileged to meet and greet him." The entire apparatus of the State was included, as a matter of course, in a religious celebration.
The media - now the bugbear of the conservatives - were completely on-side. Journalistic objectivity was sent on a long holiday. RTE's coverage of the papal Masses was delivered in the hushed, reverent tones of awed pilgrims. Its director general, George Waters, declared it "a supreme privilege for the national broadcasting authority to cover this major event".
The newspapers - and even supposedly alternative magazines like In Dublin, for which I then wrote - were almost entirely uncritical. I remember hardened journalists complaining bitterly about the irreverence of Anthony Cronin, who dared to murmur some words of dissent. This newspaper, not in general noted for its tendency towards Catholic triumphalism, headlined its leading article on the visit with a single word: "Joy" and declared, "John Paul II has spoken to all of Ireland".
"His pastoral visit has become a potential illumination for everyone on the island." In the excitement of the moment, the notion that "everyone on the island" might include the residents of east Belfast, or women using contraceptives or homosexual men and women, went out the window. Even the wonderfully sceptical Donal Foley, noting that the Pope's sermon in Phoenix Park on the evils of modernity was what he had heard "almost word for word, from the parish priest in Ferrybank, Canon Brennan, when I was a boy", felt it necessary to add that "of course, its simplicity gave joy and comfort to practically everybody".
The church had, in other words, all the ideal conditions for which nostalgic conservatives now pine. But they made, in the long run, no difference whatsoever. If anything, the euphoria gave the church leadership a false sense of security. It created the illusion that it was possible to turn back the clock.
It fuelled the anti-abortion movement of the early 1980s, leading to the Pyrrhic victory of the 1983 constitutional amendment in which the appearance of a Catholic consensus was disastrously shattered and the church's claim to speak for "everyone on the island" was fatally undermined.
The lesson, as we face the prospect of another abortion referendum, should be obvious. If the extraordinary outpouring of piety and enthusiasm that enveloped the State 20 years ago did nothing to stop the process of social change, can anyone seriously believe that going through the motions of putting another formula of words into the Constitution will have a greater effect? Looking back on the television images of Bishop Eamonn Casey and Father Michael Cleary warming up the crowd for the Pope's Mass in Galway should be enough to shatter any remaining faith in pious facades.