Mikhail S. Gorbachev won a small, painful victory in the game of musical chairs in the Kremlin, but he failed to unseat some outspoken critics of his most radical reforms.

Gorbachev's most visible success was taking the place of Andrei Gromyko as Soviet president, combining that office with the more powerful post of general secretary of the Communist Party, as did his three predecessors.And he brought some new, possibly friendlier, faces onto the ruling Politburo.

But "it is still not Gorbachev's Politburo," Stephen Cohen, head of Soviet studies at Princeton University, said Monday.

"I don't see this as a decisive consolidation of power on the part of Gorbachev," Cohen said. "As long as he is a reform leader, there is never going to be decisive consolidation. Every reform generates new opposition."

Peter Reddaway, who heads the Kennan Institute for Advanced Russian Studies in Washington, predicted that "in the next year or two Gorbachev is likely to come under increasing political pressure."

Gorbachev bought some time, said Cohen, by orchestrating "a fairly complex set of compromises by different groups on where the reforms ought to go."

For the time being, the shuffle at the top has not visibly reduced the power of the two Politburo members who have most vocally differed with the reform movement, Yegor Ligachev and Viktor Chebrikov.

In fact, it gave them authority over two of the most important areas of reform, leaving Ligachev in charge of reforming agriculture and Chebrikov in charge of reforming the legal system.

Putting Ligachev and Chebrikov in control of those reforms was intended, said Cohen, "to assure the moderates that the most radical reforms are in the hands of the least radical reformers."

Chebrikov did relinquish his job as head of the KGB security police, but he took a much more powerful post, party secretary. When Yuri Andropov made exactly the same move in May 1982, he became the front-runner to succeed the ailing Leonid I. Brezhnev, which he did on Brezhnev's death seven months later.

Ligachev's new status is less clear. He had been the No. 2 man in the Kremlin, by his own account running the day-to-day affairs of the party secretariat. Giving Ligachev the agricultural portfolio does not remove his hand from control of the party secretariat.

And it puts him in charge of food production, a sector that can make or break Gorbachev.