Beware the Dangerous Dogs Act Syndrome. As an emotional spasm passes through the body politic, the cry is not so much "Do something" as "Do anything". Legislating for moral panics is not a good idea, and most of the reactions to the MPs' expenses revelations are irrelevant, while some of them are positively harmful.
These reactions fall into three main categories: sack the miscreants; change the rules; and hold a general election tomorrow. Of these, the last is easiest to deride. David Cameron is to go round the country this week canvassing for signatures for the Conservative Party's petition for a general election. It has been suggested that it is the Leader of the Opposition's job to call for an election. Well, up to a point. It is for the Leader of the Opposition to table a motion of no confidence in the Government if he or she thinks that the Prime Minister can be brought down. And it is a debating point for the Chamber of the House of Commons: if the right honourable gentleman is so sure of popular support for this measure, why not put it to the test? But to make it the main thrust of the attack on Gordon Brown betrays a weakness.
Such a demand only raises the next question: on what great issue would such an election turn? Cleaning up Parliament? That would involve throwing out n Labour MPs, where the value of n is determined by fine judgements on a slide-rule of morality individual to each elector; approximately n Tory MPs, plus or minus an adjustment for the degree of partisanship of each elector; and a smaller than n number of Liberal Democrats and Nationalists. And it might involve electing independent candidates in certain seats where the sitting MP is deemed "totally unacceptable", to borrow the Prime Minister's language about Hazel Blears, but which are so safe that it would be difficult to remove the incumbent without special measures.
Independents sometimes achieve worthwhile ends, usually at constituency level. There is a case for Esther Rantzen. She could stand in St Helens against Shaun Woodward, her former producer at That's Life! who claimed on expenses for a second-hand copy of the book they co-wrote about Ben, the two-year old liver transplant boy.
But electing Rantzen, or Martin Bell (again) or Katie Price, would not "transform the system". The trouble with independents is that they don't stay independent. They soon fail to toe the line of conventional outrage. Richard Taylor, the independent MP for Wyre Forest, disappointed the obvious expectations of the BBC when asked on Radio 5 Live on Friday if there should be a general election now. "No," he said. Wrong answer! Doesn't he know he is supposed to be independent? How dare he think for himself and say that an election ought to be about the big issues such as the economy? But he is right. The rules are that the Prime Minister decides when to ask for an election, provided it is on or before 3 June next year, and that the rest of us make fun of him for suggesting that he won't do it yet because he thinks he'll lose. Cameron, however, should be setting out the alternative government's programme, not joining in.
In any case, the thinning-scissors of righteousness have already cut selectively through the ranks of our representatives. Frontbench posts have been lost, by Shahid Malik and Andrew MacKay. Several MPs have announced that they will not contest the election, whenever it comes. Large cheques have been returned to the public purse. Further reparations no doubt need to be, and will be, made. All this is in train, although there are details to sort out.
Why, for example, was it "totally unacceptable" for Hazel Blears to avoid capital gains tax on the sale of one of her properties, while it was fine for James Purnell and Geoff Hoon to avoid CGT on the sale of theirs? (The answer is that the Prime Minister mis-spoke, but Blears, unlike her cabinet colleagues, had defined the house as a second home for the purpose of claiming expenses, but as her main home for CGT purposes: perfectly legal, but it looked awkward.)
Beyond that, most of the reactions to the expenses hysteria are an excuse for everyone to offer their ready-made snake oils for all political ills. On the left, proportional representation is suddenly more fashionable than it has been for a decade. Alan Johnson, Labour's air-bag candidate (who might minimise the electoral damage as leader), led the call for electoral reform in an interview in last week's Independent. It was echoed by Ben Bradshaw, his deputy at Health, on BBC's Question Time.
On the right, the cry goes up for fewer politicians. Cameron has repeated his line about cutting the number of MPs by 10 per cent. Other Conservatives have demanded open primaries to choose parliamentary candidates and local referendums to "recall" MPs on the Californian model; some on the old left have reminisced about mandatory reselection.
Some of these ideas are good. Some of them even appear to be connected to the expenses issue. It would seem, for example, that MPs in safe seats have been more likely to make questionable claims than those in marginals. But is electoral reform the answer? It is claimed that voters in multi-member constituencies can choose between candidates of their preferred party. So they can, but has that made Irish politics spotless? And if we had fewer MPs, that would just mean The Daily Telegraph ran the story for 14 days instead of 16.
Others have wheeled out the full boxed set of trendy constitutional reforms, from reducing the power of party whips and increasing that of select committees, which have absolutely nothing to do with expenses.
All this overlooks the big fact that reform has already happened. Openness has held MPs to account. Many MPs have paid a heavy price. The expenses regime has already been transformed for the future. Any further reforms should be argued on their merits, and not bundled into law on the back of a public mood of vengeance.
John Rentoul's blog is at www.independent.co.uk/jrentoul