MOSCOW, NOV. 2 -- Kremlin leader Mikhail Gorbachev, reflecting new caution toward opponents within the party who have slowed his quest for urgent reforms, injected a striking tone of conservatism today into his familiar appeal for political and economic change in the Soviet Union.

In a speech that was billed as a major policy address and that he spent weeks writing this summer, the Soviet leader weakened the impact of most groundbreaking positions he has taken. Gorbachev even rebuked his personal protege Boris Yeltsin, the Moscow party chief and outspoken advocate of glasnost, or openness, who is under fire from party conservatives for criticizing the slow progress of the reforms.

By the time he finished the speech, some western and Soviet observers were struck by the softened image of himself that Gorbachev presented. "There was nothing bold there," one western diplomat said.

For example, Gorbachev coupled an attack against Joseph Stalin for committing "real crimes" with an endorsement of the former leader's brutal, widespread collectivization. After calling for closer cooperation between socialist countries and the capitalist West -- unusual for a communist leader -- Gorbachev issued a standard prediction, doctrinaire as it was dire, of the slow demise of capitalism.

Gorbachev, who just months ago complained that his calls for perestroika or restructuring, were not being enforced quickly enough, also used today's speech to criticize Soviets too eager about the reforms and to appeal to them for "revolutionary self-restraint." He warned against succumbing to the pressure of overzealous supporters of reform and "those who voice their disappointment with what they regard as a slow rate of change."

The speech, which came amid signals of hardened opposition to Gorbachev's reforms within the Communist Party leadership, buttressed a widely held view among western diplomats and some Soviets that the Soviet leader is caught in a quagmire of domestic political tensions.

Western and Soviet analysts alike regarded the speech as a series of half measures -- the apparent result of a mixture of Gorbachev's views and those of more conservative forces within the Communist Party. "It just didn't go far enough," one Soviet scientist said in an interview. "At this point in his reform campaign, Gorbachev has got to be more convincing if he is going to win support among those still sitting on the fence."

According to one view, the address reflects the influence of conservatives who cautioned publicly against the dangers of some of the reforms during Gorbachev's mysterious 56-day absence from public view in August and September.

Some western diplomats also speculated that Gorbachev had softened his remarks to reflect criticism raised during a review of the address at an Oct. 21 plenum of the party's powerful Central Committee. Others stressed that Gorbachev's topics, such as the Stalin era, excite so many passions across the Soviet Union that he had to broach them with a sense of balance.

The part of the speech considered by western analysts as most indicative of a conservative shift by Gorbachev was his veiled rebuke of one of the most outspoken proponents of Soviet reform.

"We must not give in to pressure to those overly headstrong and impatient people," Gorbachev said, "who do not want to take into account the objective logic of the restructuring." The comment was widely interpreted as criticism of Yeltsin, the Moscow party leader who, in the Oct. 21 meeting, reportedly railed against party leaders for slowing the pace of reform. Yeltsin later offered to resign under fire for his remarks.

According to some western diplomatic analysts here, some of the more conservative members of the new Soviet leadership gained a stronger foothold during Gorbachev's absence during August and September.

Chief party ideologist Yegor Ligachev and KGB Director Victor Chebrikov, both members of the ruling Politburo, gave public appearances espousing a more conservative line than Gorbachev's while the Soviet leader was away. Gaidar Aliyev, a conservative Politburo member who had disappeared from public view for several months after Gorbachev issued a harsh warning against the opponents to perestroika last spring, suddenly reappeared publicly while Gorbachev was away.

The echo of the plenum and the public appearances leading up to it are still lingering, according to one strongly held view among western diplomats here.

In a day of mixed signals, Gorbachev issued a warning against conservatives who seek to discredit perestroika. "Naturally these people never say that they oppose perestroika. Rather, they would have us believe that they are fighting against its negative side effects, that they are guardians of the ideological principles that supposedly might be eroded by the increasing activity of the masses."