First Bill English, then Chris Carter and now Rodney Hide.
Parliament's unique strain of swine flu has claimed another victim.
Another senior politician has been caught with his trotters planted firmly in the trough - the difference being that Mr Hide's affliction has been severely compounded by a simultaneous outbreak of foot-in-mouth disease.
Whether or not the remark was meant for public consumption, Mr Hide's labelling of John Key as a "do nothing" prime minister was a big mistake.
The description - patently absurd - was always going to rebound on Mr Hide given Mr Key's soaring popularity has made him virtually untouchable.
Mr Hide exhibited Act's worst mannerism - its superiority complex which in fact masks a deeper insecurity surrounding its failure to get the kind of vote at elections that other niche parties like the Greens have.
Mr Hide's belittling of Mr Key was in stark contrast to Mr Key's defence of Mr Hide only days earlier - a defence made despite the Act leader circumventing the Prime Minister's edict that ministers wanting their partners to accompany them when they go globe-trotting pay their own way.
While playing down Mr Hide's jibe, Mr Key, no doubt, will have found Mr Hide's real opinion of him instructive in their future dealings.
For his part, Mr Hide succeeded in only drawing more unwanted attention to the charges of hypocrisy that he, like Mr English, has had to answer.
In Mr English's case, the inconsistency was his dubious claim of entitlement to a living-outside-his-electorate allowance while delivering sermons on frugality as Minister of Finance.
Mr Hide was sprung taking his girlfriend on a global jaunt on the taxpayer, a revelation doubly damaging on subsequent discovery that the trip just happened to coincide with her brother's wedding in Britain.
It would have been difficult for Mr Hide to come up with a more flagrant violation of his self-ascribed image as Parliament's resident perkbuster and his party's associated promises about using public money sparingly and wisely.
Mr English's behaviour is easier to explain.
The boarding school atmosphere of Parliament rewards MPs with more perks the higher they get up the pecking order.
A mindset develops which sees the perks as entitlements to be claimed as of right - a mindset reinforced by a reluctance on the part of compliant officials to say "no" to their masters.
Mr English may have broken fresh ground in seeking permission for the Crown to rent his family home so he could live in it while the taxpayer effectively paid the mortgage.
But he was not doing anything illegal.
He was merely being innovative.
Mr English's rort was in part exposed because of the decision by Mr Key and the Speaker, Lockwood Smith, to shine the torch on previously undisclosed spending by individual MPs on travel and accommodation.
Unable to tough things out, Mr English finally caved in to public pressure and opted to take nothing.
Mr Hide is a far more complex case.
Just why he thought his travel bill would go unnoticed is a conundrum of Marie Celeste proportions.
Equally puzzling was his Marie Antoinette-like "let them eat cake" response to the brouhaha, saying he would do the same again.
It is not as though he wasn't warned of the consequences.
Attempts to dissuade him taking his partner on the trip were made by the Prime Minister's office, such was the concern about how bad it would all look.
Maybe Mr Hide, who has long given up his perkbusting crusade, simply morphed from gamekeeper to poacher.
Maybe it was the impact of a new relationship.
Maybe, it was inflated ego.
A pointer to the latter was his apology for bagging the Prime Minister which was addressed to Mr Key and "my Cabinet colleagues".
Hide is not a Cabinet minister.
He is a minister-outside-Cabinet.
The terms of Act's confidence and supply agreement with National allocates two ministerial positions outside the Cabinet to Mr Hide's party.
The arrangement - similar to the one Winston Peters had with Helen Clark - gives the minor partner more freedom to speak its mind when in disagreement with the major partner than would be the case were Act to have Cabinet representation.
Acutely conscious of how the Alliance, United Future and NZ First were effectively destroyed by being party to Government and very much intent on preserving Act's identity and independence, Mr Hide has been testing the limits of that freedom.
There is a fine line, however, between raising one's profile and the big-noting evident in his declaring that Mr Key "doesn't do anything" yet is highly popular, while Act "did everything and we are hated".
It sounded like sour grapes.
It also sounded like a cry of despair from the "death zone" of politics.
But Mr Hide can hardly blame National for Act now registering less than 1% in the polls.
Mr Key has resisted calls to discipline the Act leader, something which may anyway be impossible given Mr Hide is from another political party.
All this may have emboldened Mr Hide into thinking he too was exempt from the law of gravity.
The end result, however, is that a vast gulf has opened up between Act's supposed principles and its actual practice.
Mr Hide's thumbing his nose at his perkbuster past has cut away the moral high ground from which Act loves to campaign.
Act once described itself as the party of "values, not politics".
At last year's election, it was the party with "the guts to do what's right".
Such slogans no longer hold.
Of particular note, Act's 20-point action plan talked of cutting the Cabinet from 20 to 12 ministers so there would be "fewer baubles of office".
Rather than a bauble shortage, the baubles have been seen as there for the taking.
A key element of Act's core ideology - strict control of the public purse - has been nuked by no lesser figure than the party's leader.
John Armstrong is the The New Zealand Herald political correspondent.
