Big scandal is that Cameron failed to keep his promise
Politics is cleaner than it has ever been and further reforms are unnecessary. Nick Clegg, not for the first time, is guilty of knee-jerk politics.
A statutory register of lobbyists may well be a good idea.
Indeed, it is such a good idea that lobbyists have been begging the Government to regulate them for three years.
Since, in fact, the Government was formed on the basis of a coalition agreement that promised to legislate for a compulsory register.
What a joy for lovers of paradox. The lobbying industry has been lobbying the Government – unsuccessfully – for a statutory register to curb its activities.
And then along comes Patrick Mercer, the Conservative backbencher, and a line of lords a-leaping, including Lord Laird, and the Deputy Prime Minister suddenly remembers he promised a register after all. Yet a statutory register would not have prevented Mercer from his own spectacular folly.
If he did not think of checking whether the bogus lobbyists – actually journalists working for the Daily Telegraph and the BBC's Panorama – were members of one of the lobbying industry's three trade associations, he was hardly going to check whether they were on a statutory register.
In any case, do we really want to legislate to protect parliamentarians from the consequences of their own stupidity?
Mercer and Lords Laird, Cunningham and Mackenzie of Framwellgate say they didn't do it.
But if other MPs and lords were minded to accept cash for pressing causes, then it is probably better for the ethical quality of our legislators that they should be found out.
Yet we are still left with the apparently unsatisfactory arrangement by which Mercer has resigned from the Conservative Party, but remains as MP for Newark for another two years. The peers are currently suspended from their parties.
But if peers are found to have breached the rules – and we must assume these particular peers have not – they cannot be slung out of the House of Lords, not even if they are guilty of criminal offences.
Hence, the popularity of other proposed reforms that would help "clean up politics", according to their sponsors. Douglas Carswell, the Tory MP, wants to bring in a "recall" power, by which voters can sack MPs at any time.
But this "recall" power is wrong in principle. Imagine an MP of a governing party elected by a small margin.
After a year, the opinion polls have turned against the Government and the MP's opponent organises a petition to have him "recalled".
To make a recall power work, however, there has to be some trigger other than a petition (Clegg has suggested a finding of wrongdoing by a parliamentary committee).
But, as Carswell points out, this would look as if "Joe Bloggs MP is not being 'recalled' by local people, but sent away by other politicians".
Here, as so often, the response to the suggestion of wrongdoing in high places is to note – loudly – that it supports the case for what you thought all along. In my view, for what it is worth, it supports the argument for reforming the House of Lords.
But the main response to this scandal ought to be to praise the journalists involved for helping to keep our politics as squeakily clean as it has long been.
From the prime minister's point-of-view, there are other unsatisfactory aspects of the present lobbying scandal.
Patrick Mercer, who wishes David Cameron hadn't been born, has succeeded not only in destroying his own political career, but in further damaging the Conservative Party's image.
But, then, that is Cameron's own fault.
The statutory register of lobbyists may have nothing to do with the current cases, but it is a promise that Cameron made and which he has not yet kept. And he is the one who predicted that lobbying would be the "next big scandal waiting to happen".
This isn't a big scandal, but it is bad news for him. And he has only himself to blame.