Let's get a few things straight.

The Labour Party's spending of nearly half a million dollars from its parliamentary funds allotment on its election credit card was theft by misappropriation of public money.

The party should be prosecuted and the perpetrators who committed the malfeasance on the party's behalf should be tried and, if found guilty, sentenced and ordered to pay full restitution.

Philip Field's exploitation of immigrants and acceptance of backhanders from constituents is unpardonable and he has thus disqualified himself as a proper person to hold public office.

He should resign forthwith as an MP and never seek public office again.

Maori Party members who have received backhanders from constituents are in breach of a long-standing principle of Westminster-style democracy and in trying to justify themselves are defending the indefensible.

Hone Harawira and Pita Sharples need to change their attitudes and do a bit of homework on the culture of parliamentary practice, which is almost as old as theirs.

How on earth have things come to this? Anyone with half a brain must know by now that there is something rotten in the state of New Zealand politics and the odour of dishonesty emanating from Parliament must have citizens of the capital walking the streets with pegs on their noses.

And the sinister thing about it all is that there is not one admission of wrongdoing on the part of any of the principal players, who have raised dissembling to a new and almost deafening volume.

Helen Clark can flap her lips and point her finger at what other parties might or might not have done at the last election, and ones before that, but the fact remains that her party was told by the Auditor-General that parliamentary money was not to be used for electioneering - and went ahead and did it, anyway.

Field can insist until his dying breath that he hasn't broken the law but the fact remains that he has indulged in behaviour utterly unbecoming of a member of Parliament, irrespective of whether what he has done is legal or illegal by the letter of the law.

He, Mr Harawira and Dr Sharples can do their damnedest to justify their backhanders under the respective cultural titles of "lofa" and "koha" but their arguments are unsupportable.

As private citizens and men of standing in their cultural communities they were entitled to receive lofa and koha. But the moment they became members of Parliament they lost the right to that courtesy, and contributions from constituents became graft.

The Pacific Island and Maori cultural arguments don't wash. Parliament has a separate culture, based also on centuries of tradition, and in that culture the receipt of monetary gifts by elected representatives of the people is beneath contempt.

I can only hope that in the cases of Mr Harawira and Dr Sharples, both new to Parliament, their defence of continuing to receive koha is simply an error arising from their unfamiliarity with the political culture in which they find themselves.

Apart from Mr Harawira's obsession with smoking (or, rather, not smoking) they are a useful addition to Parliament and, once they learn the ropes, no doubt have a contribution to make.

For Mr Field there can be no such excuse. He has been around long enough to know better.

But all these shenanigans are but symptoms - or manifestations if you like - of a much deeper malaise afflicting the body politic, and that is the mixed member proportional representation system into which we were conned by cunning politicians in the early 1990s.

At the time I warned that MMP would lead to the dilution, or even the destruction, of democracy as we knew it - and it's looking more and more like I was right.

One reason politicians are prepared to push the envelopes of accepted political practice to the very limits and, perhaps, beyond, is that their loyalty is to their parties and not to the public.

There was a time when every member of Parliament was put there by the voters in his or her electorate - and if he or she didn't perform, it was outski at the next election.

But these days we can't, every three years, get rid of those who aren't up to it or who have let us down, because they'll get back in on the party list.

That half the people in Parliament are there thanks to political party patronage and, for all their protestations to the contrary, owe the electorate no allegiance or even service leaves us powerless.

When MMP came in after a referendum, we were promised that another referendum would be held on the question in 2002. Four years down the track, we still haven't had our chance to review our decision. And we won't, either.

Why? Because many of the politicians of all parties, and particularly the nuisance ones, know they'd be out of a job so fast their heads would spin.

So we can expect our politics to get slimier and slimier, our politicians to become more and more autocratic and brazen, for along with the dilapidation of our political system is the continuing unravelling of the morals, ethics and values of society as a whole - to which, of course, today's politicians are a party.

I'm glad I like bananas.