The Soviet Union is on the road to a market economy. Soviet lawmakers voted overwhelmingly this week to forsake seven decades of communist economics and endorse a plan to create a free market economy from the failed machinery of their centralized system. The challenge will be to make it work.

This is a decision of vast historic dimensions. It takes the country in such a different direction that the implications are comparable to those of the Bolshevik Revolution of 1917.If the Soviet Union survives the political and economc transformation without plunging back into harsh dictatorship - a very large "if" - it will be a Soviet Union unlike anything the world has seen before.

Today, there are serious shortages of housing, salt, sugar, bread, cigarettes and printer's ink among other things. The economy is so inefficient that crops spoil on their way to market and plants stand idle for lack of spare parts.

Of the 15 Soviet republics, 13 have either declared economic sovereignty or political independence. The trend is definitely toward less reliance on the central government in Moscow.

In the meantime, Gorbachev has been granted more power to act unilaterally to institute needed economic reforms. This may eventually be the same power he uses to bring recalcitrant republics back under one roof.

What is not clear is how successful the Soviet leader will be or how long it will take to accomplish the goals. Soviet lawmakers agreed to try to institute parts of the more radical plan of Boris Yeltsin, Gorbachev's chief political rival.

Yeltsin has set the pace in suggesting economic reform, but there will be no lasting resolution to Soviet economic maladies until he and Gorbachev come closer together.

Gorbachev's program would reverse the direction the Soviet Union has taken since the Bolshevik Revolution, and create a federation of republics with economies built on private businesses, individually owned farms and stock markets trading shares in competitive companies.

This does not sound like the Soviet Union that has been a world threat for decades. What began as a plan for "restructuring" centralized communism now seems - incredibly - on the road to destroying it altogether.

Gorbachev, of course, is not without his critics. In fact, while receiving accolades from the West for his reforms in introducing new freedoms, he has been condemned by his own people in the face of economic shortages. It is not certain they will be patient enough to allow him a chance to make a market economy work.

Another problem is that the Soviets are a long way from a Western work ethic. Workers routinely come to work late, have a cup of coffee, smoke a couple of cigarettes, work for awhile, go to lunch, then stand in line to buy potatoes. Years may pass before they understand the importance of a solid, consistent work day.

Managers must be taught to concentrate on boosting revenues and profits as much as on cutting costs.

All of this is not to say that it is impossible. It is just that the historic turn of events in Moscow is much more than a course correction.

If the necessary unity of leadership and the notably missing public support can be mustered the transformation will be something to see.

The Western world watches with approval and support, because a free market economy in the Soviet Union will benefit everyone.