Leading Article: Iran must be given the sternest warning

INTERNATIONAL terrorism in its classic form is back on the world's agenda after a deceptive interlude of calm. This week's explosions aimed at Jewish and Israeli targets in London followed an appalling attack on a Jewish community centre in Buenos Aires. Britain and Argentina, who once fought a conventional war over the Falklands, joined together to present the United Nations Security Council with a strong resolution condemning these acts. The world community has found no permanent method of curbing international terrorism. But these events could mark a beginning.

The first necessity is to reach agreement on what violent acts fall into a category suitable for the Security Council to deal with. The London and Buenos Aires incidents represent such a case. They mark the extension of political struggle - or even foreign policy - by violent means.

During the Eighties the world became accustomed to the spectacle of civilians falling victim to the contending causes and ideologies in the Middle East. There was, in effect, an undeclared conflict between the United States and its allies on one hand, and Iran and its radical Arab friends on the other. It began with the criminal seizure of American diplomats as hostages in 1979 and entered a period of remission when Saddam Hussein invaded Kuwait. It is not by any means concluded.

A clear pattern exists in the new violence. First, it is evidently the work of trained people implanted for some time near their targets. Second, the killing is committed on the territory of a third party with little or no connection to the dispute. Third, there exists ample suspicion that the terrorists benefit from the logistic and financial resources of a sovereign state. Fourth, the regime in question has a long history of using violence abroad, making foreign nationals the victims of its crimes and consistently denying responsibility for deeds that some of its leaders have directly inspired. It is the revolutionary government of Iran.

Since terrorism is essentially a weapon of politics, it must possess a political logic. The upsurge of violence coincided with a historic agreement to end the state of belligerency between Israel and Jordan. It closely followed Yasser Arafat's return to Gaza and Jericho. The Syrian government, which made the unprecedented move of televising the Israeli-Jordanian signing ceremony, may be nearer than many suspect to concluding a deal.

All this spells an end to the dreams of the most extremist elements in Iran's complex theocratic regime. In their eyes, violent action could produce two desirable results. The first is that Israeli opinion should swing back towards intransigence and rejection of territorial compromise, perhaps evicting the Rabin government in the process. The second is that the Israelis should be goaded into drastic military action against Hizbollah, the Islamic party supported and funded by Iran in Lebanon, thus ruining the chances of an early peace with Syria. Their political logic is impeccable.

It would therefore be a serious analytical mistake to confuse the limited battle between Israel and Hizbollah over a narrow strip of occupied Lebanese soil with the broader conflict between progress and religious reaction being played out in the Middle East. That is the real issue, as the people of Algeria and Egypt already know all too well, and it is the real motive behind the actions of Tehran's extremists.

The US Secretary of State's answer is to speak of the need to quarantine Iran as an outlaw state. Germany, Japan and Britain still prefer to hope that trade, diplomatic contact and reassurance may serve to moderate its excesses. The argument is now a very finely balanced one. At the very least, the sternest warning should be issued that continued terrorism will bring an economic blockade to rival those already imposed on Libya and Iraq. Iran's economy is in a dreadful state. Its rulers should ponder how long they would survive its collapse.