This is an ugly story in itself but it has become the symbol of much more since it began. As ever in politics, and particularly in Italian politics, a single event becomes the cue to fight other battles.

The story began in Naples with a demonstration more than a year ago. There were accusations of police brutality against demonstrators, which led to the arrest of eight policemen last month. This grew into a row between the judiciary and law enforcement agencies on how to deal with alleged police misbehaviour. There was also a major split within the Naples prosecutors office. Finally, the row contributed to the ongoing and dangerous tension between the government and the judiciary.

The outline of the story is easy to describe unequivocally; the detail is far more uncertain. In March last year 20,000 anti-globalisation demonstrators marched in Naples. Protesters were injured both during the demonstration and afterwards when they were in custody; damage was done to the city. Apart from arrests of protesters, 87 demonstrators were taken from hospitals where they were being treated to a police barrack, where many were reportedly beaten up. Local magistrates began investigations to discover responsibilities and prosecute alleged criminals among the police and demonstrators. A month ago they took their first action by putting eight policemen under house arrest. This is when the debate began.

The arrest of the eight police officers in Naples was interpreted by parts of the police force and Silvio Berlusconis government as an attack on all law enforcement officers and implicitly as an endorsement of the radical left by prosecutors. More moderate government and police elements did not question the prosecutors duty to investigate but they did worry that arrest, even house arrest, was unnecessary 13 months after the event. The investigators maintained that surveillance of the suspects was essential to prevent them manipulating evidence. But a court then decided that there were no grounds to keep the men under house arrest and they were freed pending the trial.

The chief of the Naples prosecutors office, Agostino Cordova, did not accept the decision of his own prosecutors and made his misgivings public, causing serious ructions in his own department and in the rest of the Naples magistrates. For their part, the Naples police began a series of demonstrations and torchlit vigils in support of their colleagues and a number of senior members of the right-wing Alleanza Nazionale party publicly declared their solidarity. The minister of justice, the Lega Nords Roberto Castelli, declared that he would send inspectors to Naples to investigate the running of the prosecution office, a clearly political use of the bureaucratic machinery which has been used against the Milan magistrature as well. The magistratures own self-governing body then passed a resolution defending the Naples prosecutors from the attacks of the minister and other members of the government, as well as those of Cordova.

The question has very quickly broadened into that major debate closely associated with Berlusconis premiership. For the last year the government has used all possible methods to discredit the prosecution branch of the magistrature. Instead of discussing whether or not individual police officers are guilty of brutality, and whether they should have been arrested, or even the broader moral and political responsibilities of the police, it looks very much like an extension of the governments fight against all prosecutors. This is a debate that will continue for a long time.

Not far in the background are the investigations into the Genoa G8 demonstrations last July, where one demonstrator was killed by a carabiniere and many others were allegedly beaten up by the police while in detention. The city too suffered severe damage. As Genoa comes under the spotlight the debate will become much hotter because of the size of the demonstration, the damage caused to the city and the injuries suffered by the demonstrators, especially as many foreigners were involved. However, there is the risk that the substantive issues are overwhelmed by the institutional battle which is closer to the prime minister than to what may or may not have happened to demonstrators in Naples and Genoa last year.