Ever since the United Nations weapons inspectors were shut out of Iraq, a year ago, the world has been left to wonder what Saddam Hussein is up to. Well, now it can be told: he has been secretly trying to transform his desert dictatorship into a world-class center for the treatment of kidney stones.

Or so it would seem, to judge from his latest purchases on the international medical-equipment market. Although Iraq remains under a strict United Nations embargo, the embargo does not cover medical supplies. Last year, the Iraqi government ordered half a dozen lithotripters, which are state-of-the-art machines for getting rid of kidney stones. (The word "lithotripter" comes from the Greek for "stone breaker.") A lithotripter uses a shock wave to pulverize these painful objects without surgery. Machines like the ones Iraq bought require a high-precision electronic switch that triggers a powerful burst of electricity. In addition to the lithotripters, Iraq wanted to buy a hundred and twenty extra switches. That is at least a hundred more than the machines would ever need.

Iraq's strange hankering for this particular "spare part" becomes less mysterious when one reflects that the switch in question has another use: it can trigger an atomic bomb. According to a knowledgeable U.N. inspector, each bomb of the type that Iraq is trying to build requires thirty-two switches. Thus, a hundred of them would outfit three bombs. It is hardly a coincidence that, as the former U.N. inspector Scott Ritter testified at a Senate hearing last year, the inspectors had "intelligence information which indicates that components necessary for three nuclear weapons exist" in Iraq. Saddam Hussein has been shopping for what he needs to make sure they work.

Iraq went to Siemens, the German electronics giant, to place the order. Before the Gulf War, Iraq acquired Siemens computers and other equipment useful for processing uranium to nuclear-weapons grade, and the company provided electrical equipment for one of Iraq's main missile sites. (Siemens has denied helping Iraq advance its nuclear program.) In this instance, Siemens forwarded the switches order to its supplier, Thomson-C.S.F., a French military-electronics company. The French government promptly barred the sale. Stephen Cooney, a Siemens spokesman, refuses to say whether Siemens nevertheless filled the switch order, or even whether the order was placed. If Siemens made the deal, Iraq got a powerful nuclear boost.

The Clinton Administration has been relatively quiet on Iraq lately. Although it maintains that it remains suspicious of Saddam, it claims to have no specific evidence that he has resumed his efforts to build weapons of mass destruction. The kidney-stone affair suggests otherwise.

The U.N. inspectors have learned that Iraq's first bomb design, which weighed a ton and was just over a yard in diameter, has been replaced by a smaller, more efficient model. The inspectors have deduced that the new design weighs only about one thousand three hundred pounds and measures about twenty-five inches in diameter. That makes it small enough to fit on a Scud-type missile. The inspectors believe that Iraq may still have nine such missiles hidden somewhere.

The inspectors have also concluded that Iraq's bomb design will work. Iraq, they believe, has mastered the key technique of creating an implosive shock wave, which squeezes a bomb's nuclear material enough to trigger a chain reaction. The new design also uses a "flying tamper," a refinement that “hammers" the nuclear material to squeeze it even harder, so bombs can be made smaller without diminishing their explosive force.

How did Iraq progress so far so quickly? The inspectors found an Iraqi document describing an offer of design help—in exchange for money—from an agent of Pakistan. Iraq says it didn't accept the offer, but the inspectors think it did. Pakistan's latest design also uses a flying tamper. Regardless of how the Iraqis managed to do it, Saddam Hussein now possesses an efficient nuclear-bomb design. And, if he did succeed in getting hold of the necessary switches, then the only thing he lacks is enough weapons-grade uranium to fuel the warheads.

The fuel, unfortunately, is getting easier to find. United States officials report that on May 29th Bulgaria seized approximately a third of an ounce of weapons-grade uranium at its border. The hot cargo, accompanied by documents in Russian, was concealed in a lead container in a pump stowed in a car. A third of an ounce is not enough for a bomb (Iraq's design, for example, needs thirty-five pounds), but this seizure and others like it show that weapons-grade fuel is beginning to circulate in the black market. Unless the U.N. Security Council can agree on a plan to reinstate meaningful inspections, Saddam may be able to complete his nuclear shopping sooner rather than later.