While the United States, Russia and other countries search for diplomatic solutions to the crisis in Iraq, the risk grows that the weapons inspectors will never again be able to do their jobs effectively. Last night, for example, Yevgeny Primakov, the Russian Foreign Minister, proposed that in return for allowing the inspectors to go back to work, their efforts would have to be brought to a quick conclusion.

If the weapons inspections are at all compromised, however, the world could face the prospect of an Iraqi atomic bomb in three to five years.

Ever since the Persian Gulf war, Iraq's nuclear weapon team has been busy designing a bomb. The latest blueprint, according to United Nations inspectors, is of a sphere measuring 32 to 35 inches in diameter with 32 detonators. The bomb would weigh less than a ton and fit on a Scud missile, the weapon Mr. Hussein used in the war to hit Israel and kill American troops.

Iraq has already successfully tested the bomb, using a "dummy" nonnuclear core. To complete it, Iraq needs only nuclear fuel, and the latest design requires a mere 35 pounds of highly enriched uranium. Inspectors believe they have destroyed almost all the equipment needed to produce such uranium, but the Iraqis know how to build or import what they need. Indeed, Iraqi scientists have made great strides in developing centrifuges, which can convert natural uranium to nuclear weapon grade. A few thousand centrifuges can produce enough high-grade uranium to fuel a few bombs per year.

Easily hidden inside an underground garage, these centrifuges would be invisible to U-2 spy planes monitoring Iraqi weapons development. Only inspectors on the ground have any hope of finding them.

Even under ideal conditions, putting a complete stop to weapons research is impossible; inspectors can't arrest scientists or read their minds. But inspectors can detect the special manufacturing needed to create fuel for nuclear weapons.

Since inspectors have been in Iraq, they have sampled soil, air and water, "swiping" surfaces to detect suspect atomic elements and flying helicopters at low altitudes to sniff out undeclared nuclear activity.

All this work gave inspectors a good chance of detecting any bombs under construction. So long as short-notice inspections were allowed, there was a good chance, too, of seizing and destroying any and all manufacturing equipment before it could be moved.

But if inspections don't resume, or are watered down, the Iraqis can reconstitute their efforts to build a nuclear bomb. In fact, they have already moved important equipment outside the range of monitoring cameras. Even if the inspection teams were to return to Iraq next week, they would have to retrieve hundreds of pieces of monitored equipment and then restart the accounting process. If Iraq resumes its weapons production, it will sink the international efforts to stop arms proliferation.

Despite these dangers, France and Russia have tried to rule out military action and to broker a compromise. Indeed, France, in its eagerness to placate Mr. Hussein, has proposed to close the books on new inspections and to rely mainly on monitoring the biological, chemical and nuclear weapons that have already been found.

But keeping track of what has already been found would not amount to a serious inspection effort -- it would be "faking it," in the words of one inspector. It would surrender all hope of finding the secret manufacturing operations -- nuclear, chemical and biological -- that remain the greatest threat posed by Iraq. There is no substitute for aggressive long-term inspections. The United States must insure that they continue.