A Mr Blair has accused a Mr Hussein of hiding arms. But who has the burden of proving their case? And to what standard? Think hard: you're on the tribunal
Prime Minister Tony Blair wants your support in the matter of President Saddam Hussein and the threat to world peace. You may have noticed that a dispute has crystallised. And since we have a dispute and you are being asked to decide which side is right … well, welcome to the world of adjudicating. Tony Blair, erstwhile barrister of this green and pleasant land, is putting his case to a tribunal 60 million strong.

Now let me give you the meat and veg for your job of adjudicating. Facts and law are meat and veg. Let's talk today about facts (law should only be considered late at night, the blood stream infused with gin and tonics). Facts, when they become quarrelled over, rely entirely on evidence. Adjudicators sometimes forget this fundamental rule. And sometimes there is no evidence worth speaking of. In which case, what does the adjudicator do?

The rule is easy, in theory: if the man with the legal burden of proof has damn-all evidence, he loses. The trouble is that the quarrelling parties frequently fail to pinpoint which party has the legal burden. Adjudicators frequently fail too.

Then there is the evidential burden of proof. Life is complicated enough when trying to fix which party, Mr Blair or Mr Hussein, has the legal burden of proof; it gets even more complicated when then trying to fathom the evidential burden of proof. It swings from party to party, though not always. Lost? Stick with me.

Some bright spark will ask, "How much proof is needed?" How much evidence will be enough to persuade the adjudicator in this case? The crucial phrase is "in this case". Sometimes the case only requires probability (Mr Blair is probably right). Sometimes, though, it requires absolute certainty (Mr Blair proves his case, if he has the burden, beyond reasonable doubt). And in this case?

Well, I suppose if the lives of tens of thousands of men, women and children in Iraq and potentially tens of thousands more across a war-torn globe are at stake, then "Oh Mr Blair is probably right" is a bit lightweight, isn't it? What shall we say? Is it that the man with the legal burden of proof has to prove this one to you beyond reasonable doubt? After all, this is not a claim for loss and expense by some fed-up plasterer on a job in Aberystwyth.

If the lives of tens of thousands of men, women and children in Iraq are at stake then the “Oh Mr Blair is probably right” decision is a bit lightweight

If Tony Blair thinks back to his days at the English bar, he might just remember rules about hearsay evidence, circumstantial evidence and relevant evidence. He may reflect on weight and probative value of evidence, or even prejudicial evidence outweighing probative value. Convicting a villain is not on simply because the fellow was once a villain. That's right, there are other curious evidential devices such as corroboration, best evidence, real evidence, credibility and more.

A bolt-hole for proof without evidence arises with "presumptions". These are combinations of facts that give rise to inferences, that then justify a package of legal rules. Tricky area if the lives of ordinary folk are resting on your decision!

Tony Blair says Saddam Hussein is hiding a ghastly array of weapons. The accuser here has the legal burden of proof. The evidential burden is on Tony Blair, too. Colin Powell cites evidence, some fair, some iffy. That evidence might swing the evidential burden to Mr Hussein for him to rebut. He tells retired MP Tony Benn that he has none. Meanwhile, Dr Hans Blix is hunting high and low for better evidence. The legal burden remains with the accuser. You are the decider. You have the issue in front of you. You must decide beyond reasonable doubt before you can condemn and kill. And if you decide in favour of Mr Blair, so be it. The world depends upon your applying the rules of evidence.