The reason is political as well as moral, financial as well as philosophical. While governments are now all too keen to lend a helping hand to today's struggling single-parent mums, when it comes to non-resident fathers the opposite has been true. Here the rhetoric has been harsher, the message tougher. Political attention has turned to bad dads - amoral dads, dads who have deserted their offspring and walked away from their moral and financial responsibilities.
Why is this? In both the US and Britain a series of social trends - the divorce epidemic, increasing relationship breakdown and a dramatic decline in marriage rates in inner cities - have combined to produce a phenomenon called "the feminisation of poverty". Crudely put, this means more and more single-parent mums dependent on benefits, more and more children in poverty and more and more fathers refusing to accept responsibility - moral and financial - for the welfare of their children.
It is these trends that explain much of the pressure to reform welfare in both countries. But in a political climate where talk of tax increases is to commit electoral suicide, the challenge both for the Democrats and now for New Labour has been to find new sources of income without imposing additional costs on taxpayers, who are after all tomorrow's voters. Hence the focus on bad dads.
In America, the first wave of change has seen states introduce punitive "naming and shaming" tactics to bully and intimidate "bad dads" into accepting their financial and moral responsibilities.
In theory this sounds perfectly acceptable but the infringements of personal liberty and the tactics chosen by many American states are shocking when you come face to face with them in practice. Massachusetts has led the way with, among other things, the power to revoke driving licences when faced with non-payment of child support.
More controversial still, posters adorn the Boston subway with photo identikits asking you if you recognise any of these "criminals". Closer inspection reveals them to be dads delinquent in their payment of child support. Massachusetts' hard-hitting campaign has been effective, and child support collections have risen dramatically. Partly as a consequence, other states have followed their lead: a number of states now have "Bad Dad" websites where worthy neighbours, friends and even family are called upon to do the right thing and snitch on those dads who are not accepting their moral (and therefore financial) responsibilities.
There is no doubt that this kind of punitive approach has its virtues. It has certainly worked to shame some fathers - predominantly middle- class ones - into accepting their responsibilities, and quite right too. However, such an approach also has its weaknesses. It can alienate and stigmatise those who are unable to pay, perpetuating vicious cycles of exclusion.
In this sense, much of the energy has been misdirected. Many "deadbeats", as Americans like to call them, are actually poor. More and more research has come to light that it's not so much that they won't pay as that they can't.
Poverty, that unfashionable word in the late 1990s, stands in the way, and posters that name and shame the poor and disenfranchised simply reinforce their sense of exclusion and injustice from a society that seems reluctant to accept its moral responsibility to them.
New Labour, which is often in thrall to the US experience, should learn the lesson. Moral outrage and platitudes about financial responsibility that bear little understanding of the realities of inner-city life may generate a cheap headline in the tabloid press but in the end they achieve little of practical value on the ground for those communities most in need.
The good (and somewhat surprising news) from the US is that the next wave of reform there implicitly recognises this. Pioneering states such as Colorado have developed sophisticated public engagement campaigns through the Governor's office involving sports figures such as baseball players with catchy headlines such as "Fatherhood is a contact sport" and "Be a hero to your child. Pay child support".
The most interesting aspect of these initiatives, and ultimately the most far-reaching in influence, is that the rhetoric of moral decline and pessimism is beginning to be challenged by a more upbeat, positive and cautiously optimistic message.
Such campaigns implicitly recognise that there is no one archetypal amoral bad dad, just as there is no one archetypal amoral single-parent mom. The vast majority of low-income non-resident fathers, like the vast majority of low-income single-parent mums, are struggling to cope and need a helping hand.
For the first time, federal (and state) resources are being devoted to welfare-to-work schemes targeted at low-income fathers, the kind of fathers trapped in America's inner-city sink estates. Of course, the resources nowhere near match the scale of the problem. But this is a historic first. The federal government now recognises that unemployed non-resident fathers, as well as single-parent mothers, need a helping hand in their efforts to gain work. At the same time, these employment- based strategies are being directly linked to other voluntary initiatives, such as parenting classes.
New Labour should learn the lessons from the American experience - namely that if society is going to preach the virtues of responsible parenthood, it too must accept its own responsibility for creating the conditions for low-income parents - fathers as well as mothers - to thrive. None of this means that New Labour's rhetoric of parental responsibility is wide of the mark, far from it. Just that it needs to be underpinned by a clearer understanding of how poverty impacts on people's capacities to act responsibly, and how, in turn, we as a society have a responsibility to tackle the causes and consequences of that poverty collectively.
The author is a London-based research associate with New York's Families and Work InstituteReuse content