The drop in the OPEC price of oil is going to have an incalculable political impact in the exporting countries. While the importers in the industrial world celebrate their good fortune, they will need to keep a wary eye on the reaction in parts of the world that are not entirely stable under the best of conditions. In the 1970s, the OPEC price became a great symbol in the world's poor countries, and particularly among Arab nationalists. It stood for economic retaliation and the righting of longstanding grievances. The break in the OPEC structure is a severe blow to pride as well as to financial balances among the exporters. It will inevitably exacerbate the hostility between OPEC's anti-Western radicals, led by Iran and Libya, and the conservative Arab states of the Persian Gulf -- particularly Saudi Arabia.

It was the Saudis who, nearly two years ago, forced the radicals to reduce their ambitions and accept an OPEC price of $29 a barrel. That, the Saudis argued, would balance the world's supply and demand, and everyone in OPEC would get richer. It hasn't worked out that way, chiefly because the world is getting along with much less of that expensive oil than seemed likely even in 1983. The Saudis have cut their production repeatedly in a dogged attempt to defend the $29 price. But the OPEC meeting that has now ended was a confession of failure. In effect, OPEC is leaving the price to the market, and the cartel has, at least for the present, collapsed. Some of the poor countries among the exporters -- Nigeria is the most important -- are already running deeply into debt. OPEC as a whole ran an international deficit on current account of about $18 billion last year, according to a prescient analysis published several weeks ago by Graham Bishop and Paul Mlotok of Salomon Brothers, the investment banking firm. The OPEC countries have learned to spend their oil money faster than seemed possible a decade ago. Curbing their present imports can't be done without great strain.

In the Persian Gulf region, any great reduction in oil income jeopardizes the whole system of subsidies by which the Gulf Arabs assist various friends and clients -- for example, Iraq in its endless war with Iran. Internally, the Saudis have used steadily increasing income to help keep the peace among the various factions of the ruling family. Whether things will stay quite so peaceful in a time of declining income remains to be seen.

For the rest of the world -- the importers of oil, rich countries and poor alike -- the fall in oil prices means nothing but good. It means faster growth, more jobs and higher standards of living -- if prices remain lower. But it's also a time for caution. You might want to keep it in mind that the two great oil crises of the 1970s began, respectively, with a war in the Middle East and a revolution.