We expect our politicians not only to be honest, but to be driven by a selfless commitment to public service. The expenses row seriously damages such noble sentiments, says Robin Wilson.
Economists have a word for it: "rent-seeking" - how an individual can exploit a position of unaccountable power to accrue incomes which do not derive from any productive activity. In recent years the label has attached to City financiers who realised they could trouser huge bonuses, regardless of the performance of their companies. But in their own small-scale, parochial, low-grade way, the farming by MLAs of expenses available to Assembly members is just as execrable.
Joe and Sinead Public will have immediately contrasted this ability to divert to their own party advantage substantial public monies furnished by the taxpayer with their own experience of insecurity, falling living standards and cuts in essential services.
Sinn Fein, the worst apparent offender, stands accused of funnelling £700,000 over 10 years to a "research" company run by the party's finance managers, which did not appear to conduct any, er, research. It also paid what seem to have been shell "cultural" societies for constituency offices it rented.
Other parties appear to have treated the expenses allowance as a general subsidy for "support" or "Press" activities. And the former Assembly Speaker, Willie Hay, felt heat he apparently never enjoyed in his constituency office when it emerged a claim had been made to offset a £4,000-plus annual oil bill.
Of course, the amounts involved are small in comparison with the annual Northern Ireland budget, whose discretionary element amounts to more than £10bn in 2015-16. Populist calls for big cuts in the cost of the devolved system, as if this would put the slightest dent in the huge further reductions that budget signals, thus miss the point.
It's the principle that is the issue. In a genuine democracy, elected representatives should be tribunes of the citizen, who argue over competing definitions of the public good. They should be driven by a selfless commitment to public service.
My father, who confined his political role to local government, swapped his dungarees and cloth cap after a hard day's work on building sites for a collar and tie, as he attended endless meetings of public bodies. One newspaper report I discovered on his death estimated him to have been a member of 90 committees and chair of 10 - he never received a penny.
Northern Ireland is not, strictly, a democracy, despite the trappings. Since the Belfast Agreement it has been what political scientists call an ethnocracy. It is a top-down system controlled by ethnic - in our case sectarian - elites, whose sole motivation is to advance the "in-group" they lead against the demonised "other".
One party negotiator in 1998 described the outcome as "an agreement to disagree" and all the barometers of relative ethnic advantage - flags, parades and how the story of the past is told - remain utterly unresolved 16 years on. With uncharacteristic transparency, the Northern Ireland Secretary, Theresa Villiers, has admitted the prospects of success in the renewed talks on these issues, which she chairs, are "slim".
Her assessment is underlined by the appallingly sectarian "curry my yoghurt" comment by the DUP MP Gregory Campbell, compounded by his buffoonery at the party conference, and the nakedly cynical remark by the SF president, Gerry Adams, that the noble ideal of equality advanced by the civil rights movement has become a "Trojan horse" for his party's nationalistic agenda.
In such a system, democratic accountability goes out the window. Why have the parties milked the expenses system? Because they can.
And how do we know? Not because of any structure for public scrutiny, but only because reporters at the public broadcaster in Northern Ireland thought the issue worth investigating and were given their head to do so.
One interesting dimension of the BBC Spotlight revelations is the individuals the programme-makers drew on as reputable moral authorities. One was Sir Alastair Graham, a former chair of the UK-wide Committee on Standards in Public Life. The other was Pat McCartan, chair of the Independent Financial Review Panel set up by the Assembly in 2011 to address salaries, allowances and pensions. The former called for an independent inquiry; the latter promised an overhaul.
Both individuals hail from the one large institution which in Northern Ireland can genuinely claim non-sectarian affiliation and a commitment to the public interest. Graham and McCartan are former trade union leaders - and it showed.
For a long time after the Agreement, for most people in Northern Ireland politics did not matter too much as they got on with their lives. Although violence rose when devolution was established in 1999 and re-established in 2007, because of the associated polarisation and instability, the embers of paramilitarism had clearly long cooled and few were directly affected.
A survey of public attitudes to devolution commissioned by the Assembly - with some naivety - was quietly placed in the public domain after it showed that respondents were less engaged by the goings-on at Stormont than by international affairs. Politics was left to the true believers, as the ethnic beneficiaries of the system, while others voted with their feet: the proportion who cast a ballot in the 2011 Assembly election plummeted by eight percentage points.
But now the mood is souring. A poll in this newspaper found that two-thirds of young people did not think Northern Ireland enjoyed peace and (unsurprisingly) a similar two-thirds wanted to leave if they could. And after years of net immigration into Northern Ireland, since 2010 thousands more people have been leaving than arriving, particularly among the under-35s - a drain of talent an already weakly-performing region can ill-afford.
Ethnic politics is always populist politics but in the end this comes ironically at the expense of the citizen. Persistent political refusal to raise the roughly-progressive regional rate, and to include within it the unpaid-for element of water, has simply meant the better-off have benefited at the expense of those more dependent on cash-strapped public services.
The mutual ethnic grandstanding over "welfare reform" brings some £200m in fines from Westminster this year and next, on top of the ravages of austerity - and the more that fails the more the chancellor, George Osborne, piles it on to shred the public realm.
So still there are floods every time the water and sewerage system, crying out for public investment, faces heavy rain. There is a crisis every time there is pressure on the accident and emergency department at the Royal Victoria Hospital and waiting times are inexorably rising, making a nonsense of official targets. And the drastic cuts in teacher numbers heralded by the budget will mean larger class sizes for every affected child and parent and less support for children with special needs.
Public apathy is thus turning to anger as it becomes evident that the ethnicised Stormont political caste is not only serially incapable of addressing everyday problems but by its actions and inactions is making ordinary citizens' lives noticeably worse.
It should be stressed - against another populist, bar-room claim, that "politicians are all the same" - that the non-sectarian Alliance and Greens parties do stand for something by way of the public good (liberalism in the first case, environmentalism in the second) and are innocent of any of these charges.
What Northern Ireland does not have is the large, secular, progressive party more evident in mainland Europe, which along with the liberal centre and the green wing could put together a workable political majority for real democracy. Anger will not turn to realistic aspiration until it does.