Leading Article: Breathe deep, count to ten, then react

In the aftermath of the bomb in Atlanta the priority is to keep a sense of proportion. It's always tempting to manufacture a panic. You extrapolate from one tragic event, one bounded very precisely by time and place, and create a looming threat. The Atlanta bomb, let's be clear, is one-off. It is unrelated to recent attacks in Dhahran and Moscow or bombing in Spanish resorts. It says nothing about the chances of the IRA striking again on the British mainland - or whether the thwarting of political pluralism in Suharto's Indonesia will give rise to political violence there. Acts of terror may occur worldwide but there is no great, global force called terrorism.

Second, however great the revulsion caused by the incident in Atlanta, the response has to be measured. There are few ways in which security can be tightened around the Olympic Games themselves; the bomb in Centennial Park was outside the security zone. But there are ways in which governments, including the American government, could overreact - and threaten the fundamental freedoms on which civil society rests.

Clinching evidence is still awaited on the cause of the crash of TWA Flight 800. Even if it was a bomb, there is nothing to link it with Atlanta. Nor ought confirmation that the flight was downed by a terrorist act provoke ill-considered actions. Holiday-makers ought not suddenly to cancel nor business travellers reroute away from Kennedy airport. Nor will they. Most sensible people will continue to fly.

It is not that they sit down and make a calculus of risk, people judge these things pragmatically. And the pragmatic judgement must be that little has changed. Most travellers would resent the further delays caused by an undue tightening of screening and baggage checks. While airline security may be of special concern in the United States - where screening techniques appear to be out of date - recent events call, on this side of the Atlantic, for nothing more than continued vigilance.

If the perpetrators of the Atlanta blast are found to belong to some domestic American insurgency the point to be reinforced is that "terrorism" is no monolith, no international conspiracy. Most terrorist acts are rooted inside particular national and historical contexts. No random act of bombing can ever be justified; but there is no point, either, in pretending all terrorists are alike. Behind the Manchester bomb is an Irish organisation, with objectives confined to the triangle of the Republic, Great Britain and Northern Ireland. Bombs on buses in Jerusalem or under cars in Madrid are the work of groups with attributes incomprehensible outside the specific histories of Israel and the Palestinians or Spain since Franco. Stopping such terrorism is never just about police officers and patrols. At some stage the Israeli foreign minister has to sit down with President Assad of Syria. It is hard to see ETA being extinguished without someone talking to someone else in San Sebastian.

For its part, the Turkish government might agree with this line of argument. It might say: the harshness which has led to hunger strikes, death and the threat of armed assault on prisoners has to do with the nature of terrorism in that country, whether perpetrated by the hard left or the Kurds. It takes, the Turks might say, strong measures to protect national integrity and there is no gainsaying the importance of Turkish integrity in a region left unstable by the dissolution of the Soviet Union. But repression has a terrible habit of breeding terrorism. Besides, Turkey wants to evolve into a trading nation based on principles of legality and individual rights: that is the only possible basis for its application to join the European Union. Its dilemma, like that of all governments including Britain's, is how to protect against terrorist acts without breaching norms of decency and proper procedure.

The answer is that there is a balance to be struck between protection of the public, the power of the state and maintenance of individual rights. That equilibrium remains as precious after Atlanta as before. The passage, 20 years ago, of the (supposedly temporary) Prevention of Terrorism Act tipped the balance in this country in favour of government and its police and security forces. Once the state acquires new powers they tend to become encrusted and permanent, despite lack of evidence of their effectiveness. In the United States, a parallel example might be the federal government's power to eavesdrop on phone conversations: one of the casualties of the Oklahoma bombing has been the reticence of judges to question applications from law enforcement agencies for permits to tap phones.

That the maintenance of liberty requires us constantly to be on our guard is a hoary old cliche. It needs updating. Maintenance of liberty in an age of terrorism requires collective self-restraint in order not to overreact, together with patience. Long experience of bombs directed against civilian targets tells us two things. Perpetrators can be found and convicted: what it takes is dedicated detective work, often of a traditional kind, not great armouries of new and intrusive state powers.

But no amount of police effort can substitute for the force of public opinion. The state is only as effective as civil society allows it to be: policing that is too aggressive or intrusive is self-defeating if it stirs up resentments and non-co-operation. Terrorists usually need domestic assistance. Even in a country as baggy and mobile as the United States, the public is often its own best protector. Yet the public's safety margins are wide - they may be prepared to tolerate a great deal more threat and risk than governments and newspaper commentators realise.