If a Prime Minister can get away with selling his people a completely bogus case for war, his Home Secretary can surely survive allegations that he helped speed up a visa application and gave his lover lifts in his official, chauffeur-driven car. And quite right, too. Thousands have died as a result of the Iraq invasion; many more have been maimed or have lost their homes. Much as one fears for the future of Kimberly Quinn and her children, the toll of the David Blunkett affair cannot be remotely comparable.
Just as Lords Hutton and Butler managed to find the necessary judicial and mandarinesque language to keep Tony Blair, along with senior ministers, civil servants and intelligence chiefs, in office, so Sir Alan Budd, in his inquiry into Mr Blunkett's conduct, should find a formula to save the Home Secretary. One could write his report now: adultery no business of inquiry; possible errors of judgement; subconscious influences; actions in good faith; no evidence of wrongdoing; everybody to carry on as normal. If the British establishment fails Mr Blunkett, having striven so mightily to save Mr Blair and all his courtiers, it will have its priorities very badly wrong. His departure on this issue would be an insult to the Iraqi victims of the war, and to the millions of Britons who opposed the invasion. It would also be an insult to those - asylum-seekers, improperly imprisoned alleged terrorists, and so on - who have suffered from Mr Blunkett's actions. If he is brought down at all, it should be because of the wrongs he has done to them.
None of this is to deny that Mr Blunkett has been a fool and possibly a hypocrite and that, if a single one of the allegations against him is true, he ought by rights to go (and by the time you read this, he may have done so). The temptation to use your position - whether it is in a public office, a profession or a private firm - to give your relatives, friends or lovers a helping hand is almost universal. The majority of people probably succumb at one time or another, usually in small ways: a discreet request that a nephew's job application doesn't go straight on to the reject pile; a few tips on how to submit a planning application; a little inside assistance in getting an appointment with a top medical specialist.
But many professions - lawyers, doctors, teachers, bankers, stockbrokers - have particular lines that are never to be crossed. In these instances, people should try not only to ensure that they stay within the rules but also to avoid any possible impression to the contrary. Thus, for example, a wise male teacher will not remain in a room alone with a sixth-form girl, particularly if he is due to mark her coursework; and a wise company director will not talk at a dinner party about a forthcoming merger.
Similarly, a wise minister will refuse even to give private advice on a matter - such as a visa application - where he or she has a personal interest. Just as a suspicion that teachers are awarding marks for sexual favours undermines the integrity of education, or a suspicion that some people are trading on inside knowledge undermines the integrity of financial markets, so a suspicion that a minister does personal favours undermines the integrity of government. This is particularly so when we are talking about a minister who has made so much political capital out of his determination to control immigration and any abuses of its procedures. In many societies, using public office to do yourself or your mates special favours is the norm. It is precisely because the temptations are so great and so difficult to resist - if only because most of us don't like to seem mean and unhelpful, and especially not politicians who have made their careers out of seeming to be "helpful" and capable of "getting things done" - that the rules are so strict. If Mr Blunkett broke them, or even seemed to, the case for his departure looks unanswerable.
Alas, politics is not so simple. It is a brutal truth of political life that the more important and successful you are, the more likely you are to get away with misdemeanours. A minor offence will bring down a junior minister, but it takes a very big offence to bring down the holder of a great office of state. That is nothing unusual: brilliant people in all walks of life get away with, say, fiddling their expenses or insulting the boss because their services are so highly valued. We judge the big people on big things, lesser people on lesser things. Franklin D Roosevelt and John F Kennedy were both serial adulterers. Conversely, Hitler was faithful to Eva Braun and kind to animals (or, at least, he didn't eat them), while Stalin was wonderful with small children. None of this changes our view of any of them. Nor, more pertinently, would our view change if Kennedy had arranged amnesties for a mistress's gangster friends (as he probably did) or if Hitler had followed his own bureaucracy's rules scrupulously (as he probably did). In politics, keeping to the rules really is for the little people. A David Blunkett can survive adultery, but a David Mellor can't - to the latter's obvious chagrin in recent days. Some ministers simply don't matter enough to be worth keeping; it isn't worth the government machine spending valuable time, effort and political capital over defending them. It was Caesar's wife who had to be above reproach, not Caesar himself.
As John Kampfner explains in our cover story, Mr Blunkett plays a role in the new Labour government which, in its leader's judgement, is irreplaceable. Therefore, Mr Blair says, he must stay. He is right. Mr Blunkett may have behaved disgracefully and inexcusably - by the standards of both private life and public life - during the throes of a doomed love affair. But whether you agree with them or not, Mr Blunkett's policies as Home Secretary are important enough to be judged on their own merits.