THE ALLIED success in throwing Slobodan Milosevic out of Kosovo left the West determined to chase the Serbian leader, an indicted war criminal, out of his own country and into the Hague tribunal. Isolation was imposed and sanctions tightened to that end. But many Europeans feel this policy is punishing mostly the people and political opposition it was meant to cheer. The opposition is now urging Washington to let up the pressure. With winter falling, Russia has seen its opening and has begun shipping in natural gas.

The immediate policy debate is over whether there will be a heating crisis in Serbia this winter. The administration, believing that lifting sanctions will reinforce the regime, doubts it. It hopes the need will be filled by fuel from Russia, from refurbished Serbian refineries, from a still-operational electric grid, from humanitarian aid and from European shipments. The administration's heating oil priority is Kosovo.

Others are not so sanguine, and lean, as we do, to testing the easing of sanctions. While there was a hope that Mr. Milosevic would not survive humiliation in Kosovo, the restrictions made sense. But with that hope fading, the rationale for sanctions shifts to driving the people to revolt, and this becomes harder for humane democratic countries to sustain. The purpose now should be to keep the edge on sanctions by fitting them to new circumstances. That means where possible targeting pressures on the regime, not the people at large, for instance, by restricting the international travel of regime figures and by rewarding the opposition for its local political successes with heating oil.

As for the Serbian opposition, it is not enough for the parties to laud democracy and protest against Slobodan Milosevic. As a condition of Western support over time, the parties should be expected to take legal and political steps against the revival of ethnic nationalism. Their goal should be to purge Yugoslav public life of fanaticism and cruelty and to build a just society.