MOSCOW, SEPT. 8 -- Should the United States provide economic aid to the Soviet Union?

As part of their meeting in Helsinki Sunday on the Persian Gulf crisis, Soviet President Mikhail Gorbachev and President Bush are expected to discuss Soviet economic reform and possible U.S. aid. The most troubling questions about aid -- whom to help and who benefits -- are being debated both in Washington and in Moscow.

Some officials have urged aid for the Soviet economy. Others have suggested investing in the economies of individual Soviet republics. Still others have cited potential pitfalls and recommended caution.

A radical economic program authored by Stanislav Shatalin, Gorbachev's closest economic adviser on his presidential council, raises the possibility of foreign investment and even a "Marshall Plan" of $10 billion to $20 billion in Western aid to the Soviet Union. Such aid, Shatalin writes, could come in the form of food shipments, credits to companies or support to the government.

Shatalin said in an interview that he is aware the West is afraid of "pouring money down a hole," but he argued that the West would be well-advised to take risks and help develop the "vast" Soviet market.

"Don't fear our market -- just be careful. If your nerves are weak, buy pills, because you'll have to be patient to deal with us," Shatalin said. "And remember, he who does not take a risk never gets to drink champagne."

According to Soviet sources, Gorbachev hopes that the United States will, like West Germany, provide billions of dollars in aid or loans with favorable conditions. In return for Moscow's agreement not to obstruct German unification, Bonn has offered to provide credits and other assistance to the Soviet Union.

When Gorbachev spoke to Bush by phone after last July's meeting of Western leaders in Houston, the Soviet leader said his nation can "survive on its own," but could carry out reforms more quickly with foreign help, the sources said.

Before leaving for Helsinki, Gorbachev met Shatalin, Prime Minister Nikolai Ryzhkov and other key economic advisers in an attempt to reconcile alternate reform plans. Secretary of State James A. Baker III is expected to review the state of Soviet economic reforms when he comes here after the summit conference.

In just the three months since the last U.S.-Soviet summit meeting in Washington, Soviet economic issues -- indeed, the shape of Soviet politics -- have changed dramatically, with Gorbachev struggling to forge a center-left coalition with Russian republic President Boris Yeltsin and with the emergence of a radical economic-reform package known as "500 Days," or the "Shatalin Plan."

Following the lead of rebellious Baltic republics, Russia, Moldavia, the Ukraine, Armenia and other republics issued declarations of sovereignty or independence from Moscow this summer and have challenged the Stalinist system of centralized economic planning and authority that has been in place for more than a half-century.

But the republics' actions -- their insistence that they, and not Moscow, have the right to control their resources and economic relations -- have led to confusion in other countries.

"Foreign business people and politicians are forever coming here and saying it's hard enough deciding whether to do business with us, but it's even harder to know with whom. Whom to help? Whom to invest in? Those are the key questions," said Mikhail Bocharov, a member of the Supreme Soviet, the nation's standing legislature, and chairman of the Russian legislature's economics council.

Bocharov argued that Westerners should ignore the Soviet economy, which he termed "a collapsed structure," and invest instead in the economies of individual Soviet republics. He is an unabashed booster of the Russian republic, sounding at times like the head of a chamber of commerce. For Western investors, he said, Russia's greatest advantage is a "huge pool of cheap labor."

"We can be as productive and cheap as Taiwan. That's it," Bocharov said, warming to the pitch. "We're a gigantic Taiwan."

But there are Soviet economists who have little of Shatalin's cool faith or Bocharov's exuberant boosterism. They fear that during the initial stages of Soviet moves toward a free-market system, the West may run the risk of doing little more than propping up old structures and filling the pockets of regional Communist Party apparatchiks who want to preserve the old system and their traditional privileges.

A new collection of essays by radical economists begins with an open letter from an ordinary Russian, Leonid Kolevtov, who counsels Western leaders: "Don't give {the Soviet leadership} money! If you really wish to see us free someday (and you say you do), if you want to get rid of wars -- do not give money to our rulers!"

Larissa Piyasheva, a radical economist, argued in an essay that Western grain sales to the Soviet Union make it easier for the Soviets to ignore the need for private and family farming. Unless the Soviet Union "gives appropriate guarantees and makes real steps towards privatization and free enterprise," she contends, "no loans or most-favored nation status should be given to the U.S.S.R."

The picture appears as clouded for business people as for the Bush administration. Jan Vanous, who heads a Washington-based consulting firm, PlanEcon, says that because of confusion stemming from recent Soviet shifts in power, he has cautioned investors. "First, I say stick to the republics and forget the all-union {Soviet} economy," Vanous said. "But even that is a big risk. For now, I'd rather see them invest in Eastern Europe."