MOSCOW -- The Soviet parliament lost its nerve yesterday at the brink of a historic decision, delegated to President Mikhail S. Gorbachev the task of choosing a plan for a transition to market economy and granted him sweeping new powers to implement it.
In a vote of 323-11, with 56 abstentions, the Supreme Soviet approved Mr. Gorbachev's proposal that he produce by Oct. 15 a single scheme to replace the centralized planned economy built over seven decades of Communist rule with a decentralized system driven by free enterprise.
A few hours later, after a fist-shaking, finger-pointing speech from Mr. Gorbachev, deputies voted 305-36, with 41 abstentions, to grant him emergency powers until March 31, 1992. In effect, he can unilaterally decree new laws on "questions related to property, managing the economy, budget and finance systems, wages and prices, and the strengthening of public order."
The parliament can "recommend to the president that he change or annul a decision," but the text of the new law does not say what happens if the president refuses.
A number of deputies accused their colleagues of shirking their responsibility by refusing to choose between the radical, 500-day economic plan named for Gorbachev adviser Stanislav S. Shatalin and the far more cautious plan of Prime Minister Nikolai I. Ryzhkov.
Sergei B. Stankevich, Moscow's deputy mayor and a member of the national parliament, said Mr. Gorbachev's insistence on combining the rival programs would lead "not to consolidation but to collapse."
Mr. Shatalin took the floor to repeat his conviction that the two plans are scientifically incompatible.
"Even the Supreme Soviet cannot cancel Maxwell's equations or Ohm's Law," he said, referring to principles of physics. "Economics, too, is a science. There can be no compromise between the program of the government and the program of the president and the Shatalin group."
Other dissenters expressed doubts about the necessity and wisdom of delegating law-making powers to Mr. Gorbachev, who now will be able to override existing law.
"We're getting presidential power that is unlimited -- I stress, absolutely unlimited -- by anything," said Leningrad Deputy Yuri Y. Boldyrev.
A small group of demonstrators outside the Kremlin yesterday morning protested Mr. Gorbachev's request. "A President -- Not an Emperor," one sign said.
Russian President Boris N. Yeltsin and the rest of the leadership of the largest Soviet republic had on Saturday officially warned -- the Supreme Soviet not to expand Mr. Gorbachev's powers.
A number of deputies yesterday said Russian fears that Mr. Gorbachev intends to dissolve parliaments, including that of the Russian Federation, were groundless. In fact, the new law does not expand Mr. Gorbachev's power to impose presidential rule and suspend the activity of local elected bodies -- a power he has held since assuming the presidency last March.
After two weeks of debate, many deputies proved to be frustrated and confused by rival economists. Others were frightened by the prospect of a rough transition to a market economy. The majority appeared glad to be able to dodge a decision and saddle Mr. Gorbachev with the choice of a plan and responsibility for its consequences.
The events of the day, in the course of which Mr. Gorbachev frequently usurped the place of the chairman of the parliament, underscored the dwindling power and prestige of the U.S.S.R. Supreme Soviet.
The 542-member body already has been put in an awkward position by the declarations of independence or sovereignty passed by most of the 15 republics, which place republican laws above union laws.
While the union parliament dithered two weeks ago, the Russian Federation parliament under Mr. Yeltsin's leadership gave preliminary approval to the Shatalin plan. Mr. Yeltsin says implementation of the plan will begin on Russian territory -- which accounts for the majority of the Soviet Union -- Nov. 1, no matter what the U.S.S.R. Supreme Soviet does.
The vote to ask Mr. Gorbachev to combine economic plans represents a victory for Prime Minister Ryzhkov. Mr. Gorbachev and all parliamentary committees but one had publicly endorsed the Shatalin plan, and the Russian parliament and a huge demonstration next to the Kremlin had demanded Mr. Ryzhkov's departure.
How long Mr. Ryzhkov's reprieve will last is unclear. Mr. Gorbachev may borrow so heavily from the Shatalin plan in drafting a combined version that Mr. Ryzhkov will feel he must step down.
Mr. Gorbachev defended his acceptance of the idea of a compromise plan by saying the public fears moving too fast to a market economy.
He said that both Mr. Ryzhkov and his "moderately radical" plan have considerable support, especially from ordinary people far from Moscow.
Mr. Gorbachev's concern for consensus reflects widespread jitters in society about growing economic chaos and political conflict -- and the possibility of a military coup in response.
Deputy Sergei V. Belozertsev caused a stir by asking why TC number of Soviet army and KGB divisions had been mobilized in and near Moscow. He claimed leaves had been canceled, units put on military alert and soldiers supplied with tear gas and other anti-riot gear.
Vladimir A. Kryuchkov, chief of the intelligence agency, took the floor to say that the troops had been moved to Moscow to prepare for the traditional Red Square military parade Nov. 7, Revolution Day, and to help with the vegetable harvest.
He also said that KGB military intelligence had reported "no troop movements that would cause concern," a statement unlikely to reassure deputies who see the threat of a coup coming mainly from the KGB itself.