As the senior correspondent for the National Catholic Reporter (NCR) in Rome he had a key assignment and broke many exclusive stories such as Rome's response to the American sexual abuse crisis, the Vatican's opposition to the U.S.-led war in Iraq, the death of John Paul II and the election of Benedict XVI.
Now based in New York, Allen is still a major figure in church coverage.
So his decision to visit Ireland and comment on the state of the church there, which he did in NCR this week, is an interesting one.
What did he find?
In one word anger.
In a few more words, Archbishop Diarmuid Martin, the reforming Archbishop of Dublin is seen as the only hope for many Catholics there but he may not be around long enough.
He writes: "Anger bred by the crisis is never very far from the surface in Ireland, among survivors themselves, inside the Catholic fold, and among a broad cross-section of the general public."
He also talks about the extraordinary stature of Archbishop Diarmuid Martin,considered to be the last remaining decent church leader in Ireland because of his determined work to ensure that responsibility is taken for the pedophile crisis.
Allen says: "Although it takes time to catch on, there’s a striking bit of Catholic locution in Ireland. When someone refers to “the bishops” or “the hierarchy,” they generally mean everyone but Archbishop Diarmuid Martin of Dublin. In the abstract, one might expect the leader of the country’s largest and most influential diocese to set the tone for perceptions of the bishops. Instead, he’s seen as an outlier for his strong approach on the crisis, including his commitment to holding church leadership accountable."
He says Martin, who is now 66 has ten years left in Dublin but may be moved sooner
As a result he writes it could be race against time for Martin to impose his will on the church in Ireland
"At 66, Martin could be in charge in Dublin for ten more years, though there’s the possibility he could be moved in the meantime. (A veteran of the Vatican diplomatic corps, he’s occasionally tipped for openings either in Rome or as a nuncio in another country.)
The question is whether Martin will be able to institutionalize his vision before he eventually moves on, or whether ten years from now Irish Catholics will still be talking about “the bishops” and meaning everyone but Diarmuid Martin."
Allen returns to the anger theme throughout his lengthy article.
He cites a priest who was himself abused speaking out at a conference in Milltown, Dublin.
"At one stage during the Milltown conference, an Irish priest and abuse survivor named Fr. Patrick McCafferty began to shout while invoking the Biblical image of the “abomination of desolation.” An audience member asked him to dial down the anger, to which his heartfelt, and transparently honest, reply was: “I am angry. I am so angry, sorry.”
When he asked members of a protest group what would satisfy then , one replied it would be seeing Cardinal Sean Brady of Armagh in handcuffs. (Brady has drawn fire for his role in a church investigation in 1975)
Martin remains the only hope for many Catholics Allen finds. At the end of a TV program he took part in he says: "an articulate and well-known survivor seated next to me, Marie Collins, interjected: “He’s the only bishop who has the support of the people!”
Incredible but true in a country that once deified its clergy.