Sam Leith from the Telegraph puts it much better than me.
'No one, whether within this country or outside is entitled to interfere with the course of our justice," is the ringing refrain of Lord Justice Moses's judgment on the Al-Yamamah fraud inquiry. It is a wonderfully fierce and lucid restatement of the principle of separation of powers and, in its context, an object reminder of why it is so important.
It says, at root, that the law is the law: and that it operates independently of political convenience, diplomatic horse-trading, and calculations of personal or even national advantage. Bravo to that.
The argument for turning a blind eye to corruption in the arms trade is much the same as the one applied against closing tax avoidance loopholes for the super-rich. And it is, for all that it gets dressed up in the pompous language of international realpolitik, a playground argument: if we don't do it, someone else will.
If we didn't call off the dogs, we were told before the Serious Fraud Office's inquiry was halted, the Saudis would buy their fighter planes from France instead of us. So, for the greater good, we ought to let this one slide.
The problem with this reasoning is that by "recognising the reality" of corruption and conniving in it, you also perpetuate it. You forfeit not only your ability to talk without hoots of derision about an "ethical foreign policy" (remember that?), but any chance of applying pressure to others. "You go first" and "just this once" are shoddy principles on which to form policy.
Say you are a shopkeeper, caught selling a 14-year-old lad a two-litre bottle of White Lightning, some fireworks and a grab-bag of huffable solvents. What sort of defence is it to maintain that "everyone's doing it" and "he would have had got it from someone so it might as well be me"?
We recognise that excuse as pathetically childish and self-serving. So why, if the person concerned is an arms dealer, do we suddenly regard this as a sophisticated and hard-headed defence of British interests and a regrettable example of the way the world wags, but there it is old boy?
Piffle, poppycock and monkey nuts. It is in the interests of Apu's Kwik-E-Mart to sell Bart the cider. But the police are there to make sure Apu serves his interests only in accordance with the law. If you are a local politician, and you're up for re-election, and the Kwik-E-Mart is one of your big supporters, you might hope to have a word with the copper, mind. And that's exactly the reason we maintain a functional separation between politicians and the judiciary.
There was enough evidence of corruption in the Al-Yamamah deal to warrant an independent investigation. That investigation, quite properly, went ahead. And it was only halted when extreme political pressure was put on those conducting it.
In the end, it was stopped after an explicit threat to withdraw a big arms contract, and an implicit threat that "lives would be put at risk" were the Saudis to withdraw their co-operation with our counter-terrorism operations. That is to announce that we're willing to do business with people who promise to connive in the murder of our citizens unless they get their way. Nice.
We're not talking about persecuting arms dealers (would that we were!): we're simply asking that if credible evidence presents itself, that they are doing business corruptly, it be investigated by independent authorities. A wealthy or powerful crook is a crook none the less, and the law is specifically set up to make sure he is dealt with the same as any other.
To allow politics to enter the operation of law is not only to make the law vulnerable, it is to make politicians themselves more vulnerable. What sort of pragmatism is that? "I have no power over the courts. Full stop," is an unanswerable response to any foreign state trying to bully a British prime minister in that department. If you let it be known you can swing the odd favour with the judiciary for your special pals, or those who threaten to let your citizens be murdered, you are asking for trouble.
So it was a disgrace that Tony Blair should have halted the investigation, regardless of whether it was in response to a threat from Prince Bandar, or whether you follow Lord Justice Moses's pointed suggestion that the threat was simply a "useful pretext" to avoid embarrassment.
It was a disgrace that the head of the SFO - whose independence from political considerations, as the judgment reminded us, is required "by statute" - should have caved in to it.
And it will be a disgrace if Gordon Brown does not, now, wipe the eye of his predecessor, allow the investigation to re-open and then keep his prime ministerial snout well out of it.