The resignation is, as Cardinal Egan himself concedes, “a form letter,” a mundane bit of curial paperwork mandated by the Code of Canon Law. Pope Benedict XVI will take the letter under consideration, and will let Cardinal Egan know when Rome has chosen a suitable successor. Sit tight till we call.

Still, no amount of routine can quash the pervasive sense that Cardinal Egan’s departure, and the prospect of a new leader of the 2.5-million-strong tribe that is New York Catholicism, is a milestone.

As the chief authority in the archdiocese, answerable only to the Pope, an archbishop really can change things, and thus an imminent transition rekindles long-frustrated hopes. The next archbishop will finally hear our pleas, the thinking goes, and enact our agenda, and in the process restore the church to some dimly remembered but undoubtedly brilliant former grandeur.

What makes the current anticipation that much greater is that Cardinal Egan himself is so unpopular. Never an inspiring or even lukewarm persona in the best of times, Cardinal Egan still might charitably have been judged a cipher to much of New York until late last year, when he picked a nasty fight with his priests.

The dispute was touched off by an anonymous letter ostensibly written by a so-called “Committee of Concerned Clergy,” who ripped Cardinal Egan as an “arrogant and cavalier” churchman who had abdicated the public bully pulpit entrusted to him because of his “unnatural fear of the media.” It called on the priests to issue a vote of “no confidence” in his leadership and on the Vatican to replace him posthaste.

Most pastors would have tossed the letter in the trash and moved on. But, in the ensuing series of meetings and rebukes and letters of seigniorial self-justification, Cardinal Egan effectively confirmed every ugly tale told about him.

“Egan is all prelate,” said a former church official who came out on the short end of one of the cardinal’s power plays. “Which is why he’s such a shitty priest.”

And so, just months away from slipping off into a comfortable retirement, Cardinal Egan instead treated the city to a full monty of his inner demons. And he continued to live down to his reputation, using heavy-handed tactics during delicate parish closings in February and ensuring that if New York Catholics weren’t anxious to see him leave before, they were more than eager to show him the door now.

BUT EVEN AS RELIEF OVER CARDINAL EGAN'S departure grows apace with perfervid speculation over his successor, it might be useful to ask a more far-reaching question: Can any cardinal of New York—the “Archbishop of the Capital of the World,” as Pope John Paul II once called the job—restore the glory days?

Other religions in the city may have had more prominence (Judaism) or more wealth (Episcopalianism) per capita. But none had the sheer size and clout and hard-earned respect of the Catholic Church. So are we witnessing the end of New York Catholicism as we knew it?

The short answer is yes.

“I don’t think the Catholic Church will ever occupy that prominent position again,” said Notre Dame’s emeritus professor Jay Dolan, the dean of American church historians. “It’s lost it.”

The longer answer may be: “Good.”

The reasons for the decline and fall of imperial Catholicism in New York are manifold and, at least for the foreseeable future, irreversible.

First off is the well-documented transformation of Catholicism in the wake of the upheavals of the 1960’s and the simultaneous reforms of the Second Vatican Council. Whereas close to three-quarters of all Catholics used to attend Mass weekly, that observance disappeared along with a compact enclave culture. If the “pray, pay and obey” descriptor of American Catholics was overdrawn before, it is, as they say, no longer operable, especially among the generation of Catholics that will come of age under the next New York cardinal.

Along with the spread of this so-called “cafeteria Catholicism” also came the breakdown of the political consensus that once lent the term “Catholic bloc” real heft. For more than a century, American Catholics have constituted the largest denomination group by far (now closing in on 65 million)—about a quarter of the voting electorate. And for much of that time, they voted reliably Democratic, especially in the big cities like New York.

Today, however, Catholics are as likely to vote Republican as Democrat, and, in fact, Catholics are often battling each other over almost anything. Once, Catholics presented a united and formidable front against a regnant and hostile Protestant society. Now, a culture of dispute and disagreement has displaced one of communion and consensus.

Moreover, there is really no one who could deliver the Catholic vote, even if it existed.

It is easy to see past churchmen, like the fearsome 19th-century bishop “Dagger John” Hughes, or the 20th century’s quintessential ecclesiastical operator, Cardinal Francis Spellman, as exemplars of what a real New York prelate was, should be and could be again. But those men reigned over a world that no longer exists.

Even the more recently departed Cardinal John O’Connor died in 2000, the year before the clergy sexual-abuse scandals broke, a “Long Lent” that has drained whatever influence the hierarchy had left. “Having your picture taken with a bishop these days is a liability,” said Mr. Dolan.

ALL OF THIS IS WELL KNOWN. What has often gone unremarked upon—perhaps because the trend is so tectonic, perhaps because the soaring infrastructure of New York Catholicism continues to fill our field of vision—is that the center of gravity in American Catholicism has been shifting away from traditional power sees in the Northeast and Midwest and toward the South and West. The migration largely mirrors the overall population migration in the country, but it is especially pronounced in the Catholic Church.

For example, while the Catholic population of New York grew in the past quarter-century from 1.8 million to 2.5 million, that 28 percent increase barely kept pace with the nationwide rise in the number of Catholics, and it pales in contrast to the huge spikes elsewhere.

The Archdiocese of Los Angeles, for one, has more than doubled, from two million to 4.4 million Catholics, cementing its pole position among dioceses.

On top of that, shortly after his election two years ago, Pope Benedict named the Archbishop of San Francisco, William Levada, to fill the slot that the Pope vacated at the Congregation for the Doctrine of the Faith in Rome. Not only is Cardinal Levada the highest-ranking Yank ever in the Roman Curia, but he has a major say in picking bishops for the U.S. church, and has shown that he favors the people he knows from the West Coast.

Yes, the next Archbishop of New York will surely be made a cardinal in due course. But he may not have the cachet that was a divine right of his predecessors.

In church terms, New York and other urban centers in the Northeast look like the Rust Belt of American Catholicism, a “mature industry” focused on the painful process of downsizing. There is, of course, wealth and vibrancy in Catholic New York—the archdiocese remains America’s fourth-largest and comprises more than 400 parishes stretching from Sullivan County to Staten Island.

But much of that is dispersing to the suburbs, where the dynamics are far different than in an earlier era. Not so long ago, Catholic New Yorkers used to identify themselves by their parish rather than by their neighborhood. Now they often pack up their car on Sundays to drive to the church of their choice.

Moreover, the practice of the faith in New York fares poorly in comparison to other places. In 1980, for instance, New York priests baptized more babies (31,000) than they did in 2005 (28,000), despite the 28 percent rise in the Catholic population. That decline runs across the board: There were nearly 10,000 church marriages in 1980, and under 6,000 in 2005; there are fewer children under Catholic instruction today, and far fewer nuns to teach them, and the number of priests has declined from 2,700 to just over 1,500.

FINALLY, AND PERHAPS MOST DOLEFULLY to the longstanding self-perception of New York Catholics, the Irish who were the architects of the golden age of Catholicism here and in much of the nation are giving way to a variegated, truly universal Catholic Church that will be more Hispanic than Irish, more devotional than dogmatic, more populist than hierarchical.

The Irish who dominated American Catholicism were able to do so for so long in large part because they got here first and staked their claim with a “bricks and mortar” Catholic infrastructure and a tribal pride that had been honed by terrible persecutions at the hands of the English. Irish Catholics were Mass-and-sacraments folk whose lives revolved around the parish. They derided the Italians as Catholics who went to church three times in their lives—to “hatch, match and dispatch.” Otherwise, Southern European Catholicism was all about street processions and popular devotions that the diligent Irish saw as kin to superstition.

Irish Catholics, on the other hand, brought their own priests with them—and kept bringing them. In 1900, two-thirds of the U.S. hierarchy was of Irish descent, and in 1970 the Irish still accounted for half of all U.S. bishops, according to Mr. Dolan of Notre Dame.

In that world, New York’s cardinal was king. No longer. The archdiocese has had only one non-Irish leader (a Frenchman who died in 1842), and the odds are strong for another Irishman to follow Cardinal Egan.

But times are changing. Much of the Irish “aristocracy” that supported New York Catholicism has moved to the ’burbs, and the same trends of disaffiliation that afflict the rest of the church are at work among Irish Catholics as well. For generations, New York Catholics wanted nothing more than to assimilate, and now they’ve gotten what they prayed for.

So is all of this such a bad thing?

“It’s a natural development that’s healthy,” argued Christopher Bellitto, a church historian at Kean University in New Jersey. “One could argue that the collapse in power is the salvation of the church.”

In the new era, New York Catholics—and their new leaders—will be gauged by the depth of their spirituality and the ability to get along with each other, rather than by their reflexive piety and parochial loyalties.

“It does call for an archbishop who can accept a different kind of a role,” said Monsignor Harry Byrne, who was ordained as a priest in New York over 60 years ago. “This is an entirely different deck of cards that we have, and they have.”

It won’t be easy to navigate this new world, but Monsignor Byrne, like many other veterans of the archdiocese, sees the challenges and changes as providential. “We can’t go back to the old days, but it is important to try to let the tensions co-exist peacefully,” he said. “The only thing without tension is a corpse.”

David Gibson is the author of The Rule of Benedict: Pope Benedict XVI and His Battle with the Modern World.

Withabankrollof$4 million, the Brooklyn-based Lubavitchers are preparing to build a tony purification bath, or mikvah, for Jewish women in the heart of the Upper East Side. But will ritual cleansing–not to mention sexual abstinence required of bathers–catch on in one of the most adamantly secular neighborhoods of New York?

As things stand now, it seems fair to believe that enticing Jewish women on the Upper East Side to ritually purify themselves after menstruating is a long shot. Then there is the present state of the narrow, four-story brick-face building on East 77th Street where the mikvah is under construction. On the outside, the century-old structure stands in grimy contrast to the rest of the tidy residences and apartment buildings, thanks to the graffiti across its doors and the scaffolding that shelters a stretch of littered sidewalk. Inside, it gets worse. The ceilings have been torn through to the roof, and the floor consists of plywood boards. In the dank basement below, chattering pumps siphon off thick brown runoff in muddy holes.

"It's not going to look like this," said Rabbi Ben Tzion Krasnianski, smiling from under his dark fedora as he stepped carefully in the dim light during a recent tour. "We are planning to build a showcase mikvah," he said. Rabbi Krasnianski has been the Lubavitch community's emissary to the neighborhood since 1992, when the sect's late leader, Rebbe Menachem Mendel Schneerson, sent him to the Upper East Side as part of the Lubavitch campaign to recruit Jewish New Yorkers to traditional observance.

The site could be up and running by Hanukkah next year, with three mikvah pools (one of them handicapped accessible) and10 preparation rooms, plus two "bridal suites" (a prenuptial mikvah trip is traditional).

The project is endowed by the likes of Bear Stearns executive James Cayne and his wife, Patricia, with additional support from donors like real estate mogul Peter Schwalbe, who is naming the baths after his late parents. Remarkably, the mikvah will be only the third of its kind in Manhattan. The Lower East Side has always had one, and the Upper West Side, with its resurgent yuppie Judaism, has a mikvah, too. But for style and elegance they won't compare to the design of the Schwalbe mikvah, with its sweeping marble archways and rooftop garden.

Note to all those Jewish women who listened to horror stories of tenement baths that were high on ritual and low on purification: This isn't your bubbe's mikvah.

"We want to change the perception of the mikvah," said Rabbi Krasnianski. That's a tall order. It's not just the generation gap–make that chasm–that separates secular Upper East Side Jews from Old World rituals like postmenstrual purification. It is also the particular Zeitgeist of Judaism in this part of Manhattan, perhaps the wealthiest and best-educated Jewish community in the world–and one of the most assimilated. Roughly 70,000 Jews live east of Central Park between 57th and 96th streets, yet the area's synagogues can seat 15,000 at most on any given Sabbath.

"By the time most Jews arrive on the Upper East Side, Judaism is a distant memory. Reform is too Jewish for them," said Rabbi Krasnianski. "If we can build a mikvah on the Upper East Side, we can build a mikvah anywhere. And if women on the Upper East Side will go to a mikvah, any woman will go to a mikvah."

No argument there.

"I think it's disgusting," said 24-year-old Jodi Basroon, as she sat with her aunt and grandmother in the New World Coffee shop around the corner from the mikvah site. "I don't know any of my friends who would go," added Ms. Basroon, who describes herself as "very Reform," attending services mainly on the High Holy Days.

In fact, none of the three generations of Jewish women gathered in the coffee shop was much enamored of the mikvah idea. "It's very old school," said Ms. Basroon's grandmother, Naomi Weingart.

Old, maybe, but not disgusting, say the mikvah's backers. In fact, they argue that the state of impurity, or "niddah," of a menstruating woman is less a physical than a spiritual condition that results from having come into contact with death–namely, the ovum and uterine lining that are expelled because there was no conception. Complete immersion in natural water is like a rebirth from that death. (Likewise, the Orthodox note, men who have come into contact with dead bodies should also dip in the mikvah. It is also used for conversions of both sexes, and for newly purchased glass or metal dishes if they are ever to be used for food preparation.)

This interplay of menstruation and mikvah, says a brochure advertising the new baths, is "the Jewish feminine mystique!"

A Modest Proposal

And tradition deems that it will stay that way, since women who visit a mikvah must arrive after dark, for modesty's sake. The baths will have a special private entrance to allow for maximum discretion.

Egon Mayer, director of the Center for Jewish Studies at City University of New York and a leading observer of Jewish life in America, argues that is just the sort of requirement that betrays the traditionalists' true views. "It is very hard for me to imagine that you could redefine this ritual for the contemporary modern American woman," said Mr. Mayer. "To me the mikvah is the most profound statement of the impurity of female sexuality. To redefine that is to walk a very fine line between faith and misrepresentation of faith. It is, shall we say, dirty pool."

But even before the Lubavitch brought their plans to East 77th Street, there were signs that some modern Jewish women were already recasting the mikvah's dynamic. This reimagining can be traced to the early 1970's and an influential essay by Rachel Adler, who saw the mikvah not as a blood taboo but as highlighting woman's central role in the divine cycle "in which all creation endlessly rehearses its death and rebirth." Ms. Adler eventually repented her notions and condemned the mikvah, but her ideas had already taken hold; women from all streams of Judaism were using the mikvah as a way of healing after traumas.

The mikvah esthetic has also been emerging in popular art. In the past two years, Manhattan has seen two exhibits on mikvah, one in Chelsea last year by 20-something New York artist Na'ama Batya Lewin (who in a 15-minute video graphically shows herself going through the intimate ritual) and a similar film display this summer at the Jewish Museum, "Water Rites," by Shari Rothfarb.

The rebirth of the mikvah can also be understood in the context of a broader resurgence in traditional practices in millennial America: Some Catholics are going to Latin Masses, Orthodox Christianity is attracting growing numbers of converts, and, of course, there is the much-discussed Orthodox resurgence among young Upper West Side residents.

A national directory of mikvahs shows a spike in the number of U.S. mikvahs from 167 in 1984 to close to 250 today. There are mikvahs in such northern exposures as Anchorage, and in Jewishly-challenged locales like El Paso and Salt Lake City. "They build them in Las Vegas, so why not in New York?" said Arlene Eis, who for years has compiled the mikvah directory for the Orthodox Union.

"It is just an incredible experience," said Alison Schneider, the Caynes' 27-year-old daughter. A Reform Jew who grew up with a Christmas tree, Ms. Schneider began to reawaken to religion a few years ago when her mother became more observant. Before she got married, Ms. Schneider made her first trip to the mikvah. "I just felt clean and beautiful," she said.

She returned to the ritual bath when she wanted to get pregnant (she has two children now), and while she is a big booster for the new mikvah, she doesn't go every month, and her basic black and gray outfit is fashion, not frumm.

"Some people go once," Ms. Schneider said. "And that's fine. It's not an all-or-nothing thing. Torah Judaism says that whatever you do is a plus. The fear is that one day you'll be living this life style"–she looked around at the elegantly appointed living room of her East Side home–"and the next day you'll be living in Borough Park and having a life that's too strict, too sad and too laden with ritual and heaviness."

Some of Ms. Schneider's friends have already taken a mikvah dip without guilt over not returning. Lauren Slifka, a 29-year-old East Side resident who doesn't keep kosher and goes to temple maybe a couple times a year, was nine months pregnant when she first heard about the mikvah ritual. She felt bad that she hadn't gone before conceiving. Not to worry. The rabbi told her she could still go and just recite a different prayer.

"You feel a connection with something a lot of women have done over time," Ms. Slifka said, her 18-month-old boy, Joshua, in her arms. But, she added, "I think it's something you can do in moderation. It's not going to be a regular part of my life."

A Strict Regimen

That's understandable, given the rigors of strict mikvah observance. It starts the first day of a woman's period. At the first sight of blood, she must have no physical contact with her husband–no kisses, no hugs, not even passing a child directly to him. And, of course, separate beds. When the last bit of blood has passed, perhaps five days later (pure traditionalists have women present a cotton swab for a rabbi to inspect should there be any doubt), the woman must count seven more days, a safety zone that rabbinical scholars built in some 1,500 years ago. Finally, after close to two weeks of abstinence (many women say it's great for the marriage), a woman can visit the mikvah.

The word "mikvah" literally means "collection of water," and the Talmud holds that the water must be collected naturally–rain or spring water, for example, pure and unsullied by human contact. An Evian bath wouldn't qualify. The modern urban mikvah gets around this problem by keeping a reservoir of rainwater handy, and just before immersion into the actual mikvah pool–a well-scrubbed and chlorinated tub–a stopper separating the natural and treated waters is removed. That allows the merest commingling of the two waters, enough to allow the chlorinated bath to "assume" a natural state.

Since the underlying tenet of the mikvah is to allow absolutely nothing between the body and the regenerative waters, a woman visiting the mikvah subjects herself to an exhaustive, hourlong "koshering," as some women call it. This means cleaning every bodily nook and cranny, from navel to nose, removing every trace of makeup, using shampoo (but not conditioner) and combing out every strand of hair to unravel any tangle. Hangnails are trimmed, scabs removed. Many women go for special depilation, but no wax must remain on their skin. After a final shower, a "mikvah lady" performs a last-minute inspection. Then the woman immerses herself completely in the mikvah, generally three times, reciting a prayer each time she surfaces. So can this really catch on with the East Side crowd?

Rabbi Andrew Bachman, a Reform rabbi who is the director of New York University's Edgar M. Bronfman Center for Jewish Student Life, is skeptical of the Lubavitch motives, seeing the mikvah as their way of drawing modern Jews into the Orthodox orbit. But he said the Lubavitch are no fools, either, and they're not about to waste time, money and effort.

"We are living in an odd time when many Jews who have detached themselves from their Judaism are seeking a seal of approval from Orthodoxy," Rabbi Bachman said. "So the mikvah is a smart move. It corners the market on that impulse."

Rabbi Krasnianski believes history is on his side. The mikvah, he notes, is the foundation of a Jewish community. In the ruins of Masada, where water-starved Jewish rebels held out against the Romans until they resorted to mass suicide, archeologists have found the remains of two mikvahs. Centuries later, diaspora Jews living in miserable conditions would trudge through wintry forests and break through frozen rivers to observe the ritual.

And a $4 million mikvah is in keeping with that ancient spirit? "Absolutely," Rabbi Krasnianski said. "Mikvah is the classiest thing. This can be a spa both for the body and for the soul." "A community becomes a community when it gets a mikvah. Not when it gets its own kosher pizza shop."