On Broadway at the moment, there is a little lament for the death of an Irish community. It's a one-man show written and performed by Colin Quinn, an actor well known in America for his work on the satirical television show Saturday Night Live.

An Irish Wake, as the show is called, is a bittersweet evocation of an Irish world of the 1970s. As Quinn tells it, that world was one in which the generations mixed freely, the young and the old eyed each other with both affection and disdain, and people shared memories, jokes and feuds. It is what most Irish people probably still think of when they hear the word "community", a kind of mutual social space in which, however mercilessly they mock each other's foibles, people retain some sense of obligation to each other.

For anyone from Ireland wandering into the theatre, Quinn's show is eerie as well as funny. The weird feeling comes from two things. One is the fact that though the language, the melancholy, and the vicious undertow in the slagging are instantly recognisable as Irish, the community he is describing was situated in Brooklyn, not in Belmullet. It's a reminder of how strong those Irish habits really were that they remained so vividly alive on the other side of the Atlantic.

And the other reason the show seems slightly surreal is that it could be happening, not in Brooklyn in the 1970s, but in Ireland now. For what Quinn is charting is the collapse of this kind of Irish sociability. His story is set around the wake for Jackie Ryan, a big figure in this small world. It is suffused with a sense of loss. The older people at the wake are frozen in a society that has lost its meaning. The younger ones are breaking free into the exhilaration and anonymity of cosmopolitan pop culture. The families are moving out into distant suburbs where neighbours eye each other's swimming pool furniture with either jealousy or contempt.

Is Brooklyn 1978 also Dublin 1998? Must the vague but powerful sense of community that most Irish people associate with their culture inevitably be sacrificed to economic progress? Whatever the answers to those questions, it is certainly true that while Ireland continues to pursue American-style riches, it could do well to ponder the American-style catastrophe that has tended to accompany them.

One of the few things that liberal and conservative, religious and secular Americans tend to agree on is that it's become very difficult for all of them to sustain a real feeling of mutual interdependence. Conservatives tend to blame everything from working women to an over-emphasis on individual rights. Liberals tend to blame racism, corporate greed and the relentless pressure of market forces. But few deny that, especially in the big cities where most of the population lives, kindness, concern and a sense of social obligation are in much shorter supply than they used to be.

One of the lessons of the American experience may be that, when it comes to preserving a sense of community, sentimental notions of an ideal world are not just useless, but actively harmful. It's easy to forget that, for Americans, the idea of community has long been even more highly valued than it is in Ireland. American movies and sitcoms were always saturated with images of decent, homogenous, mutually supportive communities.

However saccharine and corny, those images did reflect an underlying economic reality. At least within the white mainstream, Americans were in the same economic boat, all being lifted at the same time by a steadily rising tide. From 1950 until 1978, the earnings of almost all classes of Americans rose steadily. But the last 20 years have suggested that the rhetoric of loving, caring all-inthis-together community life tends to get stronger as the reality of social solidarity gets weaker. Just as Ronald Reagan was reviving the image of plain, God-fearing decent communities, the economic conditions that support a real sense of togetherness were being destroyed. Americans ceased to be on the same economic path.

On one side of the street, 1 per cent of the population owns 48 per cent of the wealth. On the other, about 15 per cent of the American population - including 22 per cent of American children - lives below the poverty line, and after 1979, the real incomes of ordinary working Americans either fell or stagnated. A report published this week suggests that, although those incomes have started to rise again, that is so only because people are working longer hours and doing more overtime. That, in turn, makes it very difficult for people to do the kind of voluntary work or to take part in the kind of social activities that keep a community together. It's very hard, with such a huge divergence of wealth, experience and lifestyle, to retain the feeling that "we're all in this together". Hard, too, to believe that Ireland will be any different if the present trends towards a growing inequality of wealth and opportunity continues.

Perhaps, though, the other lesson from America is that Irish communities don't always give up without a fight. The South Bronx, once the heart of Irish New York, provides an extreme example of the implosion of a community and a modest example of the shattered remains fighting back. Twenty years ago, in the Bronx, there was a vicious circle - the more people moved out, the more abandoned the place became; the more abandoned the area became, the more people missed the old sense of community and moved out. By the late 1970s, block after block of housing in once-teeming neighbourhoods was burned out by landlords who preferred to take the insurance money and run. The smell of burning buildings became known as "Bronx perfume".

Anne Deveney, a veteran Irish community activist now in her late 70s, recalled what happened in a recent interview on WNYC radio station: "I used to take my children to the Bronx Zoo. And on the side of the Bronx Zoo, you could see buildings torn down, buildings abandoned. And it kind of worried me. And I remember speaking to the head of the Bronx Zoo and I said `What's going on?' And he said `the South Bronx is moving up'."

With others, she began to organise what remained of the community to fight back and to halt the process of decline. In explaining her actions and her motivation, she evokes a sense of Irish community spirit: "Well, first you had to get in touch with all your politicians and explain to them `Look, if this comes up any further, you're going to be out of a job too, or else you won't like what you're working with.' And then I had to go to the investors in the banks . . . and fight to keep them in the neighbourhood - some of the banks were going to pull out. That's the Irish, you're either going to be a drunkard or you're going to be a fighter. And I didn't care to drink. I like a beer once in a while, but I prefer getting out and fighting the system."

Today, the South Bronx is no paradise, but it has recovered some of its pride and some semblance of community life. If a bit of Irish spirit can help to keep common values alive in the Bronx, perhaps it can do the same in Ireland.