Just a bunch of "kids and kooks" or the early and messy stirrings of a deeper shift in US politics? That's the question pre-occupying US politicians and assorted commentators from left to right as the one month old occupation of Wall Street spreads to a growing number of cities.

They call themselves the "99 per cent" -- representing, they say, everyone apart from the super-rich and powerful. On the left the nacsent movement has been lionised by Naomi Klein as "the most important thing in the world" with self-conscious comparisons made to the recent uprisings in Tunisa and Egypt, as well as the "indignados" in Madrid and those on the streets in Athens. In contrast, high-brow centre-right commentators view it as inchoate, unimaginative, and amateurish: all slogan, no proposal. Grow up, put on a suit and do some hard policy work is their message.

Meanwhile the Tea Party, scornful though they are of the notion that government should do more to tackle the problems of the 99 per cent, take the protestors a bit more seriously even if they they don't like to say so. Until now Tea Party activists have enjoyed a near monopoloy on grass-roots energy and righteous anger, so they are eyeballing the new competition carefully. They've been prompted to spawn their own counter-movement "the 53 per cent", representing the interests as they see it of the half of the population who are federal tax payers. (Memo to Liberal Democrats seeking to remove ever more low-earners from the UK tax-system: working people who've been taken out of the tax-system are viewed as non-contributors by the populist right). Other voices lament the fact that the cultural chasm between the 99 per cent-ers and the Tea Party is so large that it will not permit common cause to be made on one or two specific issues where there is some populist shared ground.

But perhaps most interesting is that some important establishement and centrist voices are choosing not to dimiss the protestors, which they surely would have done only a few years ago. Hence the likes of the New York Times and the Financial Times have adopted sympathetic, if questioning, stances (indeed the FT even felt moved to invoke the spirit of The Diggers -- which surely must be a first -- in a recent op-ed).

This measured response is prompted in part by the increasingly widespread reconigtion of the scale of mainstream resentment at the explosive growth in rewards going to the richest 1per cent -- and this at a time of continued public outrage about the cost of the last bank bailout (as the next one moves into view). But it's also rooted in a new appreciation of what has been happening to the living standards of most of the other 99 per cent, and a deepening sense of anxiety about what could happen if these trends persist.

There is now indisputable evidence that the US economy isn't working for what are termed middle-class families. The income of the typical American family has seen only aneamic growth for a generation. But from 2000 - 2010 these these trends worsen: the median income of families with children in the US has fallen by more than 11per cent, with a fair chunk of that fall happening before the onset of the recession, though it has deepened since (indeed 11per cent will be an understatement as incomes fell again sharply in 2011). As the chart below shows, this has cut across all racial groups -- always an important factor in US politics -- though some far more than others, with African-American families seeing a staggering 18 per cent drop in their incomes.

[Source: US Census Bureau]

Until recently one of the main virtues of the US economy -- often held up in mitigation against these long-term wage trends -- has been its powerful record jobs. Yet employment levels have been crashing over recent years, which will act as a further drag on future wage growth. The "American jobs machine" hasn't just run out of steam; it has broken down.

These challenges leave the Obama administration with little choice but to run against the economic system that it oversees. The President now regularly opines about the bad deal that the middle-class are getting: "a lot of folks who are doing the right thing aren't rewarded and a lot of folks who aren't doing the right thing are rewarded". In another echo of our own politics, Vice President Joe Biden proclaims that "the bargain has been breached."

Yet for all this rhetorical effort the Democratic leadership is nonetheless torn between different strategies for responding to this new vibrancy on the left. On the one hand, the case against embracing the new currents animating US politics is deeply institutionalised: it's been a long time since the Democratic Party successfully mobilised populist political sentiment -- and there are strong grounds for questioning its willingness to do so now, a point Robert Reich has recently made. Moreover, Obama will clearly want to fight from the centre in 2012, doing everything he can to push the Republicans to the right. He is very unlikely to think that standing shoulder to shoulder with unruly street protestors will help this cause. And for all his tough talk about Wall Street, he will also be looking for his own big money donations.

Against this is the obvious appeal of finding a way of tapping into some raw political energy, rekindling idealism and identifying some plausible enemies -- all of which Obama needs -- and which together add up to some of the key driving forces in politics. Clearly this doesn't mean signing up to all the myriad ideas emerging from the 99 per cent movement, but it does mean recognising more directly the resentments and insecurities that have sparked this new force. If handled deftly this approach could also strike a chord with the anxious American middle-classes.

As all sides look to 2012 it is clear that the anger that has surged across US society, well beyond those occupying Wall Street or attending Tea Party meetings, is a highly unpredictable and potent force, especially for an incumbent President. If Obama fails to find a way of riding and successfully steering it, then it is set to turn against him.