The DIRT affair now being investigated by the Dail's Committee of Public Accounts is one of the most serious scandals of a scandalous period in public life.
It's clear from the committee's hearings - broadcast daily on is na GaeilgeTnaG - that this is about more, much more, than tax fraud.
As the chairman of the Revenue Commissioners, Dermot Quigley, put it: "Tax administration in a vacuum is an unrealistic concept."
There was, indeed, a failure of political will in the mid-1980s when a government caved in under pressure from the banks, the opposition and some of its own backbenchers - united in resistance to the effective application of the tax.
Look more deeply. This was about a threat that, if the law were properly enforced, those who had funds, in genuine or bogus accounts, liable to DIRT, would take their money elsewhere.
Those who made the threat knew what was at stake: at least, the government's survival; at worst, the stability of the State.
With wavering Fine Gael support, the FG-Labour coalition was vulnerable. Fianna Fail, the banks and their allies made the most of its vulnerability. And, as Alan Dukes, then minister for finance, wrote in the Irish Independent on Wednesday:
"By the end of the Committee Stage Debate (on the Finance Bill) I had come to the conclusion - slowly and reluctantly - that what I still regarded as a proper, indeed essential proposal simply was not going to fly because there simply was not enough support for it in the Dail."
A common excuse for hostility to DIRT in the 1980s suggests that evasion thrives when taxes are high. It doesn't seem to follow that, when taxes fall, evasion declines.
Nor do we find, in more prosperous times, any discussion about the link between tax policies and practices and the nature of our society.
The supine posture of conservative politicians persists. So does the dominant stance of the banks, building societies and big business.
We still depend on inward investment attracted by, among other things, the lowest corporate tax rates in the European Union.
And, not only do we take advantage of hot money from other tax regimes, efforts to make our own system fairer have been few and feeble.
Payback time is, and was always meant to be, for the better off. So is justice.
As the Committee of Public Accounts tackled the regulators and the public servants turned on the politicians, it was a pity no one thought of sending for the master of zero tolerance, John O'Donoghue and his partner in probity, Dermot Ahern.
They could have explained how the State deals with fraud among the working classes and advised accordingly. Think of it: gardai and tax officials would be out in jig time stopping BMWs the way the welfare officials are rummaging through Hiace vans.
These are the divisions of our lop-sided society in practice. They, like the poor, have been with us a long time. The defenders of division say it's how things ought to be - the natural order.
The defenders of division are a smug lot: conservative politicians, economists of the Doheny and Nesbitt school, the boards of banks and building societies and, in our own trade, complacent commentators.
Their arguments are familiar. The case made now is much the same as the case made in the 1970s against the modest programme of capital taxation introduced by another Fine Gael-Labour coalition and its finance minister, Richie Ryan.
The proposed limits were high and the rates of application pathetically low. But the campaign against the proposals was long, bitter and hysterical.
By the time the opposition, the interest groups and some of our colleagues had done their stuff, the State was convinced that red revolution was at hand.
The family in the smallest cottage in the remotest parish was under threat of eviction and a widow with a decent window box was liable to be smothered in tax demands.
We could recite the arguments in our sleep. It can't be done, they said. It's too complicated. It isn't fair (what about the widow with the window box?). And, anyway, it'll drive capital out of the State.
The arguments may sound idiotic. They were. But they haven't gone away. In the 1980s the banks claimed the building societies were getting away with - well, not to put too fine a point on it, hot money.
The building societies offered certain tax advantages. Wink, wink. And confidentiality. Wink and nod. Disclosure would level the pitch.
And it did, it did. The upshot of the argument that followed the introduction of DIRT was that neither the banks nor the building societies were saddled with an effective system of accountability.
Disclosure was, in fact, left up to the institutions themselves. Pillars of society, bedad. If anyone could be trusted, they could.
They couldn't. They sorely disappointed - indeed, flabbergasted - Tony Mac Carthaigh, the committee's most convincing witness to date.
The thought of having to do more than stick a squiggle on a form was too much for them. It's a terrible thing - the joined-up writing. You'd never know who'd discover whose signature it was.
Not that there was much of an appetite for accountability in AIB. Head office sent out po-faced instructions about how to handle non-resident accounts.
Closer to the counter, competition demanded a more robust approach. No one was thanked for bringing the discrepancy to the bank's attention.
THE Revenue Commissioners treat all banks with kid gloves. Tax inspectors are not welcome inside their doors. When Mr Mac Carthaigh visited a branch in Galway he had a call from AIB's head office.
The message was unmistakable: try that again and the minister will hear of it.
These were the people who, as we heard at Dublin Castle, crawled to Charles Haughey when he was one of their clients, in turn begging him for the money he owed and fawning on him when he became leader of Fianna Fail.
Haughey threatened them and, in circumstances never fully explained, the bank eventually wrote off a chunk of his debt. Banks work in mysterious ways.
But, apart from self-regulation, which isn't effective, they're subject to regulation by the Central Bank, whose governor, Maurice O'Connell, with some of his predecessors and, no doubt, one or two of his successors, made an appearance on Tuesday and Wednesday.
Now, here's a man, you may have thought, who can explain why regulation (by the Central Bank) doesn't work any better than self-regulation by the retail banks.
Because, quite clearly, regulation - like political will - has failed.
Mr O'Connell didn't explain. Or perhaps it would be fairer to say that he may have explained but his translator was out of the room at the time.
The truth appeared to be that the Central Bank was mainly responsible for ensuring that the other banks didn't go bust.
Fine: there have been collapses and there was the extraordinary Insurance Corporation of Ireland affair. But what about the integrity of the system, which is also the Central Bank's responsibility?
Well, yes. But not in the case of non-resident accounts. That was an issue for the Revenue Commissioners.
After hours in which Jim Mitchell, Pat Rabbitte and Sean Ardagh tried to make sense of Mr O'Connell's evidence, the impression we were left with was of incomprehensible explanations punctuated by regular assertions that he was right to do what he had - or had not done.
This was Papal Infallibility as interpreted by Myles na Gopaleen. Only the defenders of division will have gone away satisfied.