MOSCOW — MIKHAIL GORBACHEV is resting in his presidential villa by the Black Sea, preparing for the resumption of the political battle this fall. Meanwhile, Russian leader Boris Yeltsin is in perpetual motion, spending a brief vacation forging political alliances with the Baltic republics and now barnstorming across the country. Judging by the time devoted to the doings and sayings of the Siberian populist on the evening television news, Mr. Gorbachev need not return to Moscow.
Mr. Yeltsin, who was elected head of the parliament of the Russian Republic last May, is now arguably the most popular politician in the Soviet Union. He enjoys the support and the trust that Gorbachev once possessed and watched fade away during the past year of economic collapse and political disarray.
Now Gorbachev has been forced to seek an alliance with his one-time rival, agreeing to revise his economic reform plans and his response to demands for autonomy within the Soviet Union along the lines of Yeltsin's policies. The political balance of left and right, which Gorbachev has used so well in the past to preserve his power, is now crucially altered.
This political axis was formally set with an agreement at the beginning of August to formulate a joint program for transition to a market economy. The program is to be based on a radical 18-month plan announced earlier by the parliament of the Russian Republic, the largest of the Soviet Union's 15 republics. The economic plan is to become, in turn, part of the basis for a new ``union treaty,'' giving greater freedom to the republics.
The deal is a slap at Gorbachev's central government, supposedly at work on the same task. ``The accord came as a complete surprise,'' wrote the independent weekly Commersant, ``taking the normally vigilant staff of the Soviet Council of Ministers [the Cabinet] unawares. This has caused rumors to fly anew that the resignation of Prime Minster [Nikolai] Ryzhkov and the Council of Ministers is imminent.''
In an interview with Latvian television, Yeltsin said that he proposed the idea of forming a joint commission in a telephone call to Gorbachev in late July from Latvia, where he was vacationing. The two men, says a seasoned Soviet political analyst, ``talk regularly - not as friends, but they have an interest in each other. It's a business connection.''
Yeltsin clearly views Gorbachev's agreement as his coup, a view shared by many observers. ``It is a personal victory for Yeltsin, since it proves he has secured the center's [represented by Gorbachev] unconditional support for his economic programs,'' Commersant wrote.
But there are those who see this as equally a case of Gorbachev using Yeltsin to push forward reforms that are blocked by conservative opponents within his government. The particular obstacle is Mr. Ryzhkov, often depicted as the representative of the ``military-industrial complex,'' a product of the vast central industrial ministries who are tied closely to the military and who oppose a diminution of their power.
``If Yeltsin believes he has won, I'm sure it is Gorbachev who has won,'' says the Soviet analyst, who preferred to remain anonymous. Since last February, Gorbachev made four attempts to get rid of Ryzhkov and failed, he explained. ``Now he is using Yeltsin to do this dirty job.''
Ryzhkov is politically associated with previous economic reform plans, including the latest presented last spring. That plan offered a three-to-five-year transition to a ``regulated market economy,'' coupled with a highly controversial rise in the subsidized prices of bread, meat, and other consumer goods.
The ``price reform,'' which some economists criticized as merely an effort to reverse the huge budget deficit, triggered a storm of protest. Radicals also attacked the program for being indecisive about setting up the structure for a market economy.
The Ryzhkov plan was voted down by the Supreme Soviet, the Soviet parliament, which asked the government to come back by the beginning of September with a new, more-detailed program. At least two groups, the State Commission on Economic Reform, headed by Deputy Prime Minister Leonid Abalkin, and a special group on alternative plans, headed by radical economist Abel Aganbegyan, have been working along the lines of that directive.
The new commission, which includes Yeltsin deputies, radical economists, and a couple of Gorbachev men, including Mr. Abalkin, is counterpoised to the Ryzhkov effort. The Russian 500-day program was actually drafted last February as part of the work of the economic reform group headed by Abalkin, says economist Grigory Yavlinsky, its main author. The plan was rejected, but got a second life with Yeltsin's new government, in which Mr. Yavlinsky now serves as deputy prime minster and head of their economic reform group.
The Soviet and Russian parliaments are now set to reconvene in the beginning of September.
Gorbachev has already indicated that he will back more-radical approaches. In the past week, the government has unveiled several presidential decrees, including one allowing the formation of small businesses and another setting up a state fund to administer the sale of some 400 state-owned companies.
Both moves reflect growing consensus in favor of moving more quickly toward privatization, the key difference, aside from pace, between the Ryzhkov and Russian plans.
``The soul of the market is competition,'' said Nikolai Petrakov, the most radical of Gorbachev's economic advisers in an interview just published by the weekly Moscow News.