That old master Gay Byrne was at it again last week.
Byrne gently encouraged the former president to discuss her ideas about the "God parent", transubstantiation, and the "core deposit of faith" that governs her life.
Their discussion brought three large issues into view.
Firstly, McAleese's faith reminds us that in some important respects contemporary Ulster Catholics are pretty different to us down here.
As I listened to her speak, I couldn't help thinking about how that kind of intense religious sensibility would play itself out in the context of a united Ireland.
Catholicism like this might make life very difficult for an education minister like Ruairi Quinn, who is currently going toe to toe with the Catholic bishops over control of Irish schools.
As such, might Ulster Catholics actually be a drag on secularisation in some future united Ireland context?
Might the ghosts of hardline Northern Catholic bishops like Cardinal MacRory, Bishop Daniel Mageean and Bishop Farren of Derry rise up again in a united Ireland to thwart an urban liberal like Ruairi Quinn?
The second big issue to arise from the interview then was McAleese's heartfelt attack on the Roman Catholic belief that homosexual life is "intrinsically disordered".
Her eloquent dismantling of this doctrine helped in some respects to wipe away the enduring shame that clings to some of the things written during the Dudgeon case on gay rights at the European Court of Human Rights.
Dudgeon had been swept up by these laws and subjected to humiliating and invasive interrogation by policemen who rifled through his private diaries.
Nineteen judges heard his cry for help at Strasbourg and 15 of them agreed that he had suffered an unjustified interference with his right to respect for his private life.
There was one Irish judge on this panel, Brian Walsh (1918-1998), but he shrugged his shoulders and chose to rework the "intrinsically disordered" doctrine.
"A distinction must be drawn," Walsh noted solemnly, "between homosexuals who are such because of some kind of innate instinct or pathological constitution judged to be incurable and those whose tendency comes from a lack of normal sexual development or from habit or from experience or from other similar causes but whose tendency is not incurable.
"So far as the incurable category is concerned, the activities must be regarded as abnormalities or even as handicaps and treated with the compassion and tolerance which is required to prevent those persons from being victimised in respect of tendencies over which they have no control and for which they are not personally responsible."
McAleese's polished performance helps dilute this kind of poison -- a poison all the more potent in its day due to its phoney veneer of charity.
The third important point then about McAleese's interview is a slightly more abstract one, one that only struck me after I watched the interview for the second time.
McAleese's liberal credentials on issues like the ordination of women and gay marriage suggest the existence of some happy mid-way point in Catholic life between heresy and extremism.
Her own struggles with what she called "the discipline of love" suggest if only by implication that you can strip away the bad stuff in Roman Catholicism and cling to a nourishing core.
This is a seductive way of thinking, one that still shapes the way we talk about our Constitution.
Some people still say that the "core" of our Constitution is an American-style bill of rights and a vigilant, guardian-angel Supreme Court.
We are asked to simply ignore the fact that our Constitution is dedicated to the doctrine of the Trinity, a doctrine that tore Europe apart for centuries after the Reformation.
We are also asked to forget things like the fact that for decades after 1937, the Irish government took your tax monies and mine and used them to fund Maynooth College, a Catholic seminary whose sole purpose for years was the production of Catholic priests.
The point in all this is that Mary McAleese's easygoing and utterly sincere emphasis on ecumenical fraternity masks the core function of all religions.
All major faith groups are designed by definition to exclude.
The faithful are offered a choice; if they want salvation, they must not look for what was convenient to themselves, but for what has been decided long ago in nature's chancery.
Religions are also in competition not just with each other, but with the State for access to its resources.
Irish Catholicism sank its teeth into the State's tax revenues in the Thirties, having pretended it was no threat to anybody by dropping the insistence on acquiring formal legal status as a State church.
And that was a very smart move for them.
Ecumenical rhetoric always runs the risk of masking the ugly competitive reality of religion, as does the attempt to pretend that Catholicism can somehow divest itself of the kind of paranoia Justice Walsh exemplified in the Dudgeon case.