The new Criminal Justice Bill is the first salvo by the Minister for Justice, Mr O'Donoghue, in his promised war against crime. Crime was prioritised by all the political parties in the last general election and Mr O'Donoghue's vague and over-hyped notion of zero tolerance was, arguably, Fianna Fail's trump card, ensuring its narrow victory.

The last government oversaw the introduction of the Criminal Assets Bureau; Operation Dochas; a very considerable expansion of prison places; the bail amendment allowing for preventive detention; and seven-day detention for suspected drug barons. It also made a commitment to both an independent prisons board and an independent courts service.

However, for the first time in this State, significant progress was also made by the Rainbow Coalition government in tackling the underlying causes of crime. For example, the first drug-free prison regime was initiated, local drug task forces were set up in deprived, drug-infested areas and, under the Rabbitte initiative, £34 million was committed for anti-drugs and youth development programmes.

These real achievements and this unprecedented level of general activity in the criminal justice area were not acknowledged by Mr O'Donoghue, who consistently characterised the Rainbow Coalition's anti-crime measures as "paralysis, resulting from a lack of awareness of the problem".

The public relations success of the zero tolerance notion in the election campaign is illustrated by the fact that the then government parties hardly mentioned their achievements, especially not their attempts to balance being tough on crime with being tough on the causes of crime. They probably feared that their efforts to achieve balanced policies would be electorally damaging in an immature political climate intolerant of anything other than overtly draconian approaches.

In this context, it is hardly surprising that the opposition spokespersons on justice are now lining up to lambaste the Minister's Criminal Justice Bill. There is clearly a deep desire to inflict on Mr O'Donoghue some of his own potent medicine. This desire is increased by the fact that the crime issue has almost faded from view in the media since the election and by the perception that the Minister for Justice has been given a very soft ride in his first few months.

However, the Minister may learn how quickly this can all change with the outraged reaction to the current law-enforcement crisis, involving the arrest and release of members of an alleged cannabis importing gang. This trumpeted Garda triumph may well turn to ashes and already has echoes of the Judge Lynch delisting debacle that almost cost his predecessor, Mrs Nora Owen, her job.

Mr Jim Higgins, of Fine Gael, has described the Bill as a "damp squib and a flawed one at that" and Ms Liz McManus, of Democratic Left, has said the Bill "demonstrates that the Minister's pronouncements on zero tolerance were little more than pre-election macho posturing".

These criticisms are well-deserved, for there can be little doubt that the new Bill is no more than a token gesture towards the full-blown notion of zero tolerance which Mr O'Donoghue so effectively exploited to discomfort the former government. As a means of ushering in an era of zero tolerance, whatever that might mean, the Bill is less than impressive.

Most people will agree that a minimum sentence of 10 years for trafficking in substantial amounts of drugs is quite appropriate. But there are aspects of the Bill which are quite radical and momentous in their implications.

The Criminal Justice Bill has two main goals. The first is to ensure that custodial sanctions for serious drug-trafficking are set and maintained at a high level. This may well be needed to undergird the deterrent value of sentences, especially in a "revolving door" penal system.

The Bill proposes to disbar drugs traffickers from benefiting from the early release mechanism. The provision in the Bill for the automatic pursuit of the criminal assets of convicted traffickers appears eminently sensible.

But there are obvious problems with this type of all-or-nothing legislation. The cut-off point at which a minimum 10 years becomes mandatory is when the drugs have a value of £10,000. The valuation is to be decided by the Garda. The street value of drugs is a volatile economic variable which can depend on the success and scale of seizures by gardai.

The Bill can also be criticised because there are no distinctions made between soft drugs and hard drugs, like heroin, which are far more detrimental in their effects.

But there are other problems and consequences with this kind of rigid, punitive approach. For example, it is likely that the real bosses behind the drugs trade will take effective measures to distance themselves from the handling of the product, exploiting addicts for this work.

But the most radical aspect of the Bill is the move towards restricting judges in their discretion to choose the most appropriate sentence for an individual case. This breaks new ground and does so in a precipitate manner in the total absence of debate about the issue and of empirical evidence on sentencing.

It is especially regrettable that the public has not been afforded an opportunity to hear the views of judges. The vacuum of information and analysis on the vital function of sentencing is highly detrimental to the system and surely should be addressed before embarking on fundamental changes affecting judicial discretion.

The second main goal is to streamline and speed up criminal justice procedures. This aspect of the Bill is likely to be popular and has raised little comment because it is perceived as addressing an area in urgent need of attention. It is widely believed that parts of current criminal justice procedure are unwieldy and not appropriate to modern circumstances, as well as being weighted in favour of defendants.

The Bill has addressed this area by proposing the abolition of the preliminary hearing and by freeing gardai from the necessity to attend court in person in certain circumstances. While it is right to eliminate unnecessary, time-wasting procedures, the issue of the preliminary hearing goes to the heart of justice and of the due process nature of our system.

The preliminary hearing has always been thought essential in order for the defendant to gain timely access to the facts of the case against him or her and in order that a judge is empowered to throw out manifestly weak cases.

The new Bill safeguards the rights of the accused relating to access to evidence, but the abolition of the preliminary hearing is nevertheless another attack on the traditional legal protections for suspects and defendants and also, like mandatory minimum sentences, on the discretionary powers of judges.

It is particularly worrying because it extends the anti-defendant agenda to all defendants, rather than just drugs barons, and because no systematic monitoring of the effects of the changes is proposed.

Dr Paul O'Mahony is author of Criminal Chaos: Seven Crises in Irish Criminal Justice