Credit cards and politicians go together like oil and water: which is why there will be much gnashing of teeth at the latest folly concerning our Parliamentarians and their inability to follow the most simple of rules relating to expenditure.
The present matter involves ministerial credit cards, a facility granted to MPs of such rank, to give them access to money should they be required to spend it in the course of their official duties.
It should be noted not all MPs have such cards, nor indeed choose to use them if they are entitled to.
Regardless, the rules surrounding their use are plain: the ministerial handbook - wherein the rules and laws pertaining to ministerial allowances, privileges and expected standards are set down - states that "use of a credit card for personal expenditure (regardless of the intent to reimburse) is not permitted".
For good measure, the words "is not permitted" are underlined.
Further, users of cards must get a tax invoice/receipt for all purposes, attach receipts and credit card slips to a signed reconciliation form, and include the reason for, and an explanation of, the expenditure.
With such clear-cut instructions, it is stretching the bounds of credulity that senior ministers of the Crown have apparently had difficulty understanding the ground rules around their cards, and as much as it is in keeping with his relaxed leadership style to deal to an issue with reprimands and a determination to "move on", there is some political danger for Prime Minister John Key should he be seen to continue to "suffer the fools" in his Cabinet - and there are invariably one or two in every administration - gladly.
For the public generally are not fools, nor do they appreciate been taken as such: verge-of-tears apologies will wash only so many times.
In this context, Housing Minister Phil Heatley must have used up about as much rope as Mr Key will lay out to him.
Earlier this week, it was revealed that Mr Heatley had used his ministerial card for personal purposes, including wine at a National Party conference, a cinema outing for his family, a Burger King meal, and a variety of other meals and expenses incurred when his family accompanied him on a "ministerial trip" to the top of the South Island.
Some of these were subsequently reimbursed, but not all.
The minister's use of the card was an unambiguous abuse of the rules under which they are issued.
Likewise, in the case of senior minister Gerry Brownlee, the $151.90 that he clocked up in taking his electorate staff out for lunch was out of bounds.
As one of the most experienced ministers in the House, Mr Brownlee ought to have known better.
Subsequent to the revelations, both MPs apologised to the Prime Minister, to the public and, in Mr Heatley's case, to his electorate, and promised to pay any outstanding monies back.
Mr Key explained to an exasperated public that the matter could be put down to a combination of mistaken credit card identity and "stupid" mistakes, rather than any intention to "rort" the taxpayer.
He then slapped all concerned over the wrist with a wet bus ticket, and displayed - in case the ministers' own remorse was deemed insufficient - both additional contrition, and anger.
Much as he would like them to, however, the questions may not end there.
Political observers with a memory beyond the end of last week will recall that Mr Heatley attracted a degree of opprobrium for an earlier housing expenses furore, the one that eventually centred around Finance Minister Bill English.
They will also be comparing notes with the infamous British MPs' expenses scandals that threatened the very integrity and standing of Westminster last year.
So there is a context to this latest hiccup in the National-led coalition's generally smooth exercise of government, and it is one that should have made ministers more guarded and careful about their expenses.
Further, it is valid to consider what the affair might imply about a minister's general capabilities; or, in the alternative, his character.
Sensibly, several of the ministers do not have such cards, and others, including Mr Brownlee, have now given theirs up.
For his part, Mr Key may need, sooner rather than later, to put away his smiling Mr Reasonable personage and show at least a glimmer of the inner steel that all successful leaders must possess.
Whatever else her qualities, indulgence to wayward or embarrassing ministers was not Helen Clark's style.
She cut loose ministers on several occasions when their actions were seen to have fallen short, or threatened to contaminate her Government's larger agenda.
Mr Key is a very different leader than Miss Clark.
He is determinedly his own man, and much liked because of it, but in this matter he might do well to take a second look at his predecessor's methods.
When actions of ministers of the Crown trail a whiff of incompetence, or worse, dishonesty, the entire enterprise is put at risk.
