It might be easier if he'd say what it was he'd done, but perhaps his genes won't let him tell us. The excuse that his genes made him do it seems to be the part of his resignation speech that got most noticed; even if, like most really well remembered phrases, it is something he never said. What he in fact blamed were "genes and experiences".
But society is twitchy about genes at the moment. They have come to stand in place of gods as the divinities that shape our ends; this is bad theology and bad biology, but it makes for great funding applications.
The clearest statement I know of what is wrong with the view that genes are responsible for all the interesting things about us was made by Richard Dawkins, in his second book, The Extended Phenotype, which contains a long and scrupulous description of the ways in which genes cannot possibly control what happens to the bodies they specify.
"If I have two copies of a gene G, nothing save mutation can prevent my passing G on to all my children. So much is inexorable. But whether or not I, or my children, show the phenotypic effect normally associated with possession of G may depends very much on how we are brought up, what diet or education we experience, and what other genes we happen to possess. So, of the two effects that genes have on the world - manufacturing copies of themselves, and influencing phenotypes - the first is inflexible apart from the rare possibility of mutation; the second may be exceedingly flexible."
And, of course it is the second possibility that we are interested in. Genes as gods and alibis are far more interesting than genes as strings of DNA. But the trouble with gods is that we are responsible for them ourselves. I'm not saying they don't exist. They exist just as certainly as money does; and they display a distressing independence of our will, just as money does. But they would not exist at all without conscious, deliberate human decisions.
Genes as strings of DNA wouldn't exist without us, either: if humans stop breeding their DNA disappears. But this is not really a moral consequence. What is interesting about gods is that we bear some moral responsibility for them, at the same time as they really are more powerful than we are. It is possible to overcome some of our most deeply programmed genetic instincts, such as the fact that fire hurts, and pain is to be avoided - think of Thomas Cranmer holding his hand in the fire until it was completely burnt.
But we can do this only by calling other instincts and emotions into play, and they, too, build on genetic foundations.
We can to some extent choose which instincts we will gratify. We can make these choices easier by habitually repeating them, until they no longer require choice at all. But the one thing the gods can never offer us is freedom from choice.
In England it is widely understood that divinity, like morality, is largely concerned with sex, and that genes are just a respectable word for horniness. But if those desires are controlled by genes, so must be the contrasting longings for respectability and lasting monogamy. Hunter Thompson quotes frequently Dr Johnson's remark that "he who makes a beast of himself escapes the pain of being a man" - but the Doctor was wrong. A man who tries to make a beast of himself simply becomes a divided, anguished beast.
Bad news for Ron, then. But the real charge against him is not that he tried to blame it on genes. That is less serious, perhaps, than blaming it on his parents, though he tried that a little, too: his father, we learn, was a monster. If this really was the determining factor in his character, perhaps he should have made more of it when he was offering himself to the Welsh people as their representative. It is certainly less ridiculous than blaming the media. It's no use accusing us of intolerance when he won't even specify what we're supposed to be tolerating.
What is horrible about his excuses is that they ignore the degrading truth about all of us. We are all, in fact, politicians, manoeuvring for support among shifting coalitions of desire every day; and when we get it wrong, and our government is overthrown, we have only ourselves to blame.
Andrew Brown's book `The Darwin Wars' is to be published by Simon and Schuster in February