Leading Article: The jury system: bulwark of liberty, or perverse anachronism?

Louise Woodward's conviction for murder was a miscarriage of justice. Even acknowledging that despite extensive live coverage on satellite television nobody in Britain has heard all the evidence that was before the court, two points are unarguable. One is that there must be reasonable doubt about Ms Woodward's culpability in the death of baby Matthew Eappen, which could have been caused by a pre-existing or an accidental injury. The other is that, even if she did harm him, the prosecution was in no way able to prove that it was premeditated and committed with malice, the definition of second-degree murder in Massachusetts. (By not handing down a verdict of first-degree murder, the only thing the jury acquitted her of was extreme cruelty.)

The most serious charge which could conceivably be justified by the evidence was manslaughter, or even assault and battery, which was the original charge.

There is some evidence that Ms Woodward was a neglectful childcarer, but none - apart from the inconclusive nature of Matthew's injuries - that she was violent. It is hard not to share the view of Barry Scheck, the defence lawyer, who sounded rather unlike the flamboyant showman he is alleged to be. "I do not understand how anyone in their right mind could come to this verdict," he said.

So should we condemn the system of American justice, or simply the perverse verdict of one group of 12 Americans? The first point to be made is that it is neither British arrogance nor anti-American to say that there are aspects of the Massachusetts system which are inferior to the criminal justice system in the United Kingdom. The use of the legal system as a platform for political ambitions, and the right of the defendant to choose the verdicts available, seem to have combined to leave the jury with no option but to go for an excessively harsh sentence if they did not want to acquit. It seems that the state's original charge was raised to murder by Thomas Reilly, a district attorney who wanted to appear tough on crime in order to further his ambitions to run for Attorney-General of Massachusetts. If Ms Woodward had then asked for the lesser charge of manslaughter to be considered, this would inevitably have been read as a partial admission of guilt.

There are several other aspects of American judicial systems which are bad, although they do not seem to have contributed to this particular injustice. The absence of restraint on pre-trial publicity, and indeed on emotional interviews during the jury's deliberations, must operate against the chances of a fair trial - although televising court proceedings may not in itself be a bad idea.

Of course, there are respects in which American systems are better than the British. American judges, for example, are more representative of their society than British ones. And recent English legal history has a less-than-proud record of a succession of miscarriages of justice - often on the basis of forced or false confessions.

But there is a bigger question, which must be asked on both sides of the Atlantic: are juries really the bulwark of civil liberties, or are they now an anachronism? In the Woodward case, as in many criminal trials, the jurors seem to have been influenced by emotion rather than evidence, while in complex fraud trials it is almost impossible to secure convictions - complexity itself often seems grounds for reasonable doubt.

It has long been an article of liberal faith that juries are unpredictable and sometimes perverse, but that this is an essential safeguard against a legal system becoming an arm of the state and suborned by political interests. Landmark verdicts, such as those in the Ponting and Marchioness cases, when juries famously cocked a snook at judges' instructions, are held up as beacons of citizens' liberty.

And so they should be. But the jury system cannot be preserved, fossilised, for all time. There is evidence that committees tend to make worse decisions than individuals - and that the inter-personal dynamics of a group of 12 makes it likely that decisions will swing arbitrarily between extremes. But there is hardly any evidence about how juries actually work in practice. This must change, and the sacred cordon drawn around their deliberations (in the UK) should be lifted after each case. Meanwhile there is plenty of evidence that juries are unrepresentative, with recruitment carried out in secret and the articulate and assertive most likely to be excused. Both Americans and Britons want to be tried by jury, but do not want to serve on them: this lack of civic responsibility must be corrected. But it would be wrong to decide, on the basis of one case, that jury trials were inherently unfair.

And it would be wrong to condemn the American justice system out of hand, at least until Judge Hiller Zobel has had the chance to throw out the jury's verdict on Tuesday.