This isn't to say that MPs don't court disaster by making shameless use of their families as electoral props. And we enjoy the stories even more if we can find some spuriously high-minded reason to underpin our pseudo- indignation - like the rather flimsy Soviet connection in the case of Jack Profumo a generation ago.
But if there isn't one - and there usually isn't - our appetite remains limitless. It does not matter in the least whether the politician is good at his job, like Tim Yeo, who was forced into resigning as a minister at the Department of Environment. Or at the most menial level of government like Piers Merchant, who was caught out over an affair with a 17-year- old Soho night club hostess, and who has since reacted to his exposure with utter tastelessness.
Pretending to be concerned for the wretched spouse and family, we are none the less happy to see them writhing helplessly on the rack while we devour every detail until the politician himself is finally driven out of office. This is still genuinely baffling to - say - our fellow Europeans who are used, frankly, to a better class of scandal. But it may help to explain why Michael Heseltine yesterday found it so much more imperative to put the black spot on Piers Merchant than on Neil Hamilton.
In mid-term Mr Merchant might have got away with resigning his unpaid job as a Parliamentary Private Secretary. He might even, as the transport minister Steve Norris did, have escaped altogether. In an election such an embarrassment just can't be risked. We are all enjoying the story too much.
It was nevertheless a peculiar position for Mr Heseltine to take. He, of all people, has little reason to defend Mr Hamilton, much less say, as he did to Sir David Frost last Sunday, that he would be happy to campaign in his constituency.
It is not only that politically they are poles apart. Or that Mr Hamilton has now admitted to a second stay at the Ritz and claiming a free airline ticket as a business expense for Revenue purposes. Or that he has confessed to taking payments from the lobbyist Ian Greer, which he declared neither to the Inland Revenue nor to the ministers he and his colleague were lobbying on behalf of Mr Greer's client US Tobacco. It is also that Mr Hamilton has even specifically admitted misleading Mr Heseltine about his relationship with Mr Greer when he was confronted with the original allegations in 1994.
The most bizarre aspect is that the Deputy Prime Minister should nudge towards resignation Mr Merchant, who has not been guilty of any misconduct relating specifically to his parliamentary duties, and leave intact Mr Hamilton, who patently has. If Mr Merchant should go, why on earth not Mr Hamilton?
The most complacent explanation for why the scandals which overtake British politicians are most frequently sexual has been that they are so unscandalous in other ways. Unlike some of their Continental counterparts the honourable members are so, well, honourable. Ours is, we constantly tell ourselves, a corruption-free system. Politicians aren't bought in this country as they are in others. The problem, as Mr Heseltine knows perfectly well, is that this comforting wisdom no longer looks so wise.
Enough is now known about Sir Gordon's Downey's inquiries - and the admissions made to him by Neil Hamilton and his fellow Tory MPs Michael Brown, Michael Grylls and Mr Smith - to puncture it. Especially as the payments investigated by Sir Gordon were only identified because the man who who knew most about them, Harrods' owner Mohamed al Fayed, had a grudge against the government and Conservative Party - because of the criticisms made of him in a DTI report over a decade ago.
He had a reason to blow the whistle. Most people tempted to pay off MPs don't. Which means you can't exclude the possibility that undisclosed payments were enjoyed by a group even larger than those caught in the Downey/Al Fayed net. But even if they weren't, the problem with the generic term "sleaze" is that it puts something which matters a lot - cash for questions, undisclosed lobbying interests, and cheating the Inland Revenue, on the same level as something that doesn't: Mr Merchant making an idiot of himself in a Beckenham park.
The argument, of course, is that the investigation of Mr Hamilton is not yet complete, that unlike Tim Smith, MP for Beaconsfield until his resignation on Wednesday, he has not publicly confessed, and that it would be "unfair" if he were forced to stand down. But even if Mr Hamilton had not already confessed to enough to make him unfit to serve as an MP, that misses an important point exposed both by Mr Heseltine's broad hint to Mr Merchant yesterday and John Gummer's later endorsement of it as a Conservative press conference.
Why do the party hierarchs want to see Mr Merchant go? Because he is a liability and a distraction. Do they seriously think that Mr Hamilton won't be a liability in Tatton? Or Mr Brown in Cleethorpes? It is actually rather bad luck on constituents of his who want to vote Conservative in Tatton but are just a little too fastidious to vote for Mr Hamilton. Which, to judge by the blunt speaking of at least one of his ward officers, may be quite a lot of people.
It's true, as Paddy Ashdown admitted - with admirable frankness since it was his own party which set the Downey report alight as an issue last week - that so-called "sleaze" isn't as decisive a topic for the electorate as crime, the NHS and economic policy. But the continued candidacy of Mr Hamilton - and to a lesser extent his colleagues - will remain a liability until polling day: the monkey on the back of the Conservative campaign.
Mr Hamilton is a politician standing for office - no more, no less - and political methods should be used against him. Certainly, local Conservative associations enjoy an autonomy that local Labour parties no longer have - an anomaly which any post-election Tory leader will surely seek to change.
Tim Smith was done for on Wednesday because of both mounting criticism in his own constituency and, less fully reported, a clear message conveyed to him by the Whips' Office in London that he had lost the support of ministers and backbenchers. Something similar now needs to happen to Mr Hamilton pretty fast. It no longer matters whether Mr Major prorogued Parliament to try to avoid the Downey controversy breaking - or whether it would anyway still have taken weeks, if not months for the Standards and Privileges Committee to deliberate on it, as Mr Major's defenders say. Whether Mr Hamilton stays or goes will tell us quite a lot about whether the Tories yet understand the need for real change in the culture of Parliament; whether Mr Merchant stays or goes will tell us very little at all.Reuse content