AMONG THE MANY astonishments of the final session of the National Conference of Catholic Bishops -- which was supposed to be a "debate" on its pastoral letter about nuclear weapons, and which, in fact, sounded like an antiwar demonstration -- was the fact that nobody mentioned Ronald Reagan by name, and nobody said, "Support our president."

Another name that was not not mentioned -- there was no need to -- was that of Pope John XXIII, whose spirit totally dominated the gathering. He was that rotund, smiling revolutionary, who threw open the windows of the church, and gently tugged the clergy's gaze from heaven, and the problem of getting there, down to earth, where people have troubles meriting prayerful consideration.

Few echoes of the pre-Johannine church were heard. One bishop said that the salvation of man from sin took precedence over his mere survival -- "Our striving is not for survival but for resurrection." He was a lone voice.

There was not a single reference to Reagan's disarmament efforts in Geneva. A facetious reworking of his campaign slogan, "Stay the Course -- for Peace," brought many baritone chuckles among the black suits around the tables in the Capitol Hilton.

There were, to be sure, calls for a more militant attitude toward the Soviet Union, a suggestion that the feelings of the Catholic military be taken more into account, and one plea for a "little flag waving" and patriotism. But another speaker said the bishops should apologize for the dropping of American atomic bombs in 1945 -- "because of not having raised our voices then as we do now."

Doubts were heard about the ability of the flock to accept so radical a doctrine as the "immorality" of nuclear war from an organization that never managed to say a definitive word about Vietnam. It would be "divisive" said the undercover hawks. But others dismissed the danger. A bold peace statement could bring back the fallen away -- make them proud to be Catholics again -- a bishop from Saginaw declared. It would also be "a step towards ecumenism."

Even the restrained dissenters felt constrained to praise the draft, and to thank the drafters.

It was a wipeout for the White House. None of its initiatives about the unseemliness of men of the cloth venturing into strategic matters -- the right of the document to exist, in other words -- were reflected in the two- hour discussion, in which all, in consequence of Vatican II collegiality, were treated equally. A counter-pastoral from the White House, the work of William P. Clark of the National Security Council, was a tactical and a strategical disaster, the hawks conceded in corridor conferences.

Bishops are not accustomed to reading their mail in the morning paper, and the leaking of the letter to The New York Times occasioned vast umbrage among a group whose emerald rings, emblems of office, are still occasionally kissed by the faithful. The general disdain for the clumsiness -- and substance -- of the counter-offensive was conveyed by a gray-haired, pipe-smoking cleric, who said, "Clark? -- isn't he the fellow who didn't know where Europe was a year ago?

A generation ago, many of them had been arguing about the ethics of parish bingo. Social teaching was limited largely to a consideration of the sixth commandment -- sex education began and ended with the word "No." A younger speaker hinted at these past preoccupations. Wouldn't it be wonderful, he observed, if the bishops studied marriage with the sensitivity and delicacy it is according nuclear weaponry.

John XXIII has changed the face of the American hierarchy beyond recognition. A persistent strain of Third Worldism is there -- and support for the U.N., as a peacemaking institution. They obviously do not read The Reader's Digest in their rectories. If they did, they would know, as the president purports to, that they are dupes of the Kremlin when they favor a freze.

The ultimate rejoinder to his latest slander of freezeniks came from John Cardinal Krol of Philadelphia, a profoundly conservative cleric, who is not accustomed to having his anti-Red credentials questioned. "Don't talk to me about that," he grimly told a knot of brother bishops, "I'm a Pole."

Some seemed to take issue with the pope's acceptance of nuclear weapons as a deterrent to nuclear war. No outright defiance, mind you, but one speaker complained of the "circular, confusing and contradictory" character of the deterrent argument.

The bishops voted overwhelmingly for a third draft of their historic and revolutionary pastoral.

John XXIII would have been proud of them.