When the history of the Soviet Union's hungry winter of 1990-91 is written, the usual culprits will be cited: inefficiency, planning failures, diversion of food to the black market and farmers' withholding their output for higher prices.

But an unusual culprit will also be noted: the Soviet Army, which monopolized the railroad network for its own purposes and worsened the food shortage.The bizarre story starts in 1988, when the 16-member North Atlantic Treaty Organization and the communist bloc's six-member Warsaw Pact met to work out a treaty slashing conventional arms in Europe.

From the start, two points were clear. The two alliances would end up with equal numbers of weapons. And the communist side would have to give up more because of its huge superiority in tanks, artillery, combat planes and the like.

After more than two years of painstaking bargaining, President Bush, President Mikhail Gorbachev and 20 other NATO and Warsaw Pact leaders signed the Treaty on Conventional Forces in Europe last Nov. 19 in Paris.

Bush and Gorbachev were euphoric. It was "the most far-reaching arms agreement" ever negotiated, said the American. "What a long way the world has come," Gorbachev exulted.

The numbers looked too good to be true. Between the Atlantic Ocean and the Ural Mountains, each alliance would be limited to 20,000 battle tanks, 30,000 armored vehicles, 20,000 artillery pieces, 6,800 warplanes and 2,000 helicopters.

Those limits meant drastic cuts in the weaponry the Warsaw Pact had before the talks. And they appeared to lift NATO planners' nightmare: a massive tank-led invasion of Western Europe.

For example, the Kremlin had 46,000 tanks in Europe in 1988. The new treaty limited it to 13,300. U.S. arms experts anticipated that Moscow would have to destroy tens of thousands of tanks.

As the signatories gathered in Paris, however, disturbing stories appeared. In one of history's largest military deployments, the Soviet Army had moved heavy weapons behind the Urals - and thus outside the treaty's scope.

"An enormous amount of equipment went east of the Urals," reports a British defense official. "We're still trying to tie down the figure, but it could be over 70,000 pieces of equipment - tanks, artillery, other things."

Literally substituting guns for butter, the army tied up Russia's rail system. Part of the largest grain harvest in Soviet history and other crops failed to reach the shops, adding to discontent with Gorbachev's rule.

Now, if Moscow wants its subjects to go hungry, it's not America's business. But a major violation of the spirit of a key disarmament agreement is a cause for concern. What do they want with all that iron in Siberia?

Also, signs point to violations of the letter of the treaty. Moscow is required to tell NATO how many weapons it has. Its initial declaration seems to be 20,000 short. And three regular army divisions appear to have been redesignated as "naval infantry" not covered by the treaty.

At his February summit with Gorbachev in Moscow, Bush should make clear that traditional Russian cheating on arms treaties goes against Gorbachev's vaunted "new thinking."

Bush should insist that the arsenal spirited east of the Urals be defanged. If Gorbachev is replaced by General X or KGB chief Y, which cannot be ruled out, those tanks could roll west again on short notice.