How far should the United States and the United Nations go in helping and protecting Kurdish refugees in northern Iraq?

This is not an easy question to answer. Much depends on what is meant by "help."British Prime Minister John Major suggested this week that a U.N.-guarded safe haven be carved inside Iraq where fleeing Kurds could find sanctuary in the north and Shiite Muslims in the south. Kurdish leaders and refugee committees have endorsed the idea - with reservations.

While Iraq's ambassador to the United Nations has rejected the proposal, Major's approach would be to go ahead whether Iraq agrees or not. U.N. forces in the area - mostly American - still have the muscle to enforce any such decree.

Certainly, the urge to help some 2 million Kurds who have fled their homes into the snowy mountains in Turkey, Iran and northern Iraq after Saddam Hussein's armies crushed their short-lived rebellion is understandable.

An airlift of supplies by the United States, Britain and France to the starving and freezing Kurdish men, women and children was begun this week, but is only reaching a fraction of those in need.

The numbers are numbing. Some 400,000 to 700,000 Iraqi civilians, most of them Kurds, have fled just across the border into Iran. Another 500,000 to 700,000 are massed on Iraq's side of the border. About 270,000 have escaped into Turkey and another 250,000 are still on the Iraqi side of the Turkish border. In each location, the country is rugged, cold and inhospitable on both sides of the borders.

Why not set up an enclave in northern Iraq for these suffering people? There are several concerns.

- While few would object to the U.N. thrusting itself into Iraq's affairs in a humanitarian effort on behalf of the Kurds, even over the objection of the Iraqi government, the move would set a risky precedent. Most would not like to see the U.N. take upon itself the power to intervene directly and physically in the internal affairs of a nation against the wishes of the national government, however odious. Who knows where such authority might be exercised next time? Or on what grounds?

- Such refugee enclaves, even though always seen as a temporary relief measure, often turn out to be more or less permanent. Two examples: The Gaza Strip is a U.N.-supervised region filled with Palestinian refugees for more than 40 years; more than 300,000 Cambodian refugees who fled the slaughter of the Khmer Rouge were settled in a sliver of land along the border and are still there 10 years later, supplied with daily water and food by the U.N.

- Once a people are moved, unless they return fairly soon, the land they left is usually taken by others. Saddam might be tempted to get rid of his "Kurdish problem" in oil-rich areas by settling other Iraqis there and refusing to let the Kurds return. Huddled in the mountains, the Kurds, even if they can be adequately fed and given shelter, will have far less than they had in the lands they left behind.

Clearly, the refugees must be given food, medicine and shelter - and quickly. But the best solution would be for them to return to their homes, with guarantees of safety against reprisals.

This may require U.N. observers, not an occupying army. The U.N. still has the oil embargo to use if Saddam seeks to punish the Kurdish uprising or take vengeance beyond what has already been done.

But such U.N.-backed guarantees must be spelled out clearly - and the swift economic consequences of further atrocities made plain - so that the Kurds can begin to make their way home. This should be done quickly before thousands more die and inertia sets in.