MOSCOW — IN the teeth of profound public skepticism, but gambling on a decisive show of strength, Russian President Boris Yeltsin yesterday ordered troops to restore order in the rebel republic of Chechnya.
Three columns of Russian armored vehicles were in position for an assault on Grozny, the capital of the breakaway region, where troops loyal to self-declared President Dzhokhar Dudayev prepared to do battle.
But the intervention, aimed at quashing Chechnya's three-year-old declaration of independence, seemed to be as much a heavy-handed negotiating tactic as an invasion.
''There is no question of an invasion, or storming Grozny,'' the head of the government press office, Valentin Sergeyev, said. Instead, he explained, the Russian advance would halt some distance from the capital, pending talks.
That delay seemed designed to give Mr. Yeltsin a chance to avoid a possibly costly war that would weaken his popularity at home.
Moscow has always insisted that Mr. Dudayev accept that Chechnya is part of the Russian Federation. Dudayev, drawing on centuries of hostility to Russia in the mountainous North Caucasus, has refused.
Chechen forces were not expected to be capable of much, in the early stages, against a determined Russian military intervention. ''Dudayev has only a few hundred regular organized troops,'' pointed out Pavel Felgengauer, military correspondent for the liberal daily Sevodnya.
The Russian task force, comprising regular Army troops and Interior Ministry soldiers, was instructed to ''restore constitutional order'' in the republic, where Dudayev's men have been fighting a sporadic war against Moscow-backed insurgents.
The advancing troops were ''appealing through a loudspeaker for peaceful citizens to lay down their arms,'' the government press agency Itar-Tass reported. That appeal was presumably directed also to the ragtag militia that opposes Dudayev, which Moscow has been arming and assisting for several months.
The failure of those militias to unseat Dudayev has prompted Moscow to act directly, according to some analysts here. ''When it became clear that the job could not be done by ''Chechenization,'' they had to go in and do it themselves,'' suggested Rashid Kaplanov, an expert on Caucasian ethnic questions.
But military involvement in Chechnya is unpopular among ordinary Russians, and Yeltsin is taking a calculated risk that intervention will have a dramatic enough impact to force a speedy solution to the crisis.
In a poll carried out two weeks ago, a Moscow polling organization found that 74.2 percent of Russians believed Moscow should recognize Chechnya's independence. Fewer than 40 percent believed the government's argument that events in the southern republic were a threat to Russia.
Ever since Yeltsin first hinted that he might use force in Chechnya, opponents of that policy -- including liberal members of parliament -- have warned that it would only unite Chechens around Dudayev and against their historic enemy, Russia.
Chechen leaders have even threatened a ''second Caucasian war,'' recalling Russia's 100-year struggle in the 19th century to subdue the fiercely independent clans and tribes that populate the Caucasus mountains.
Russian officials have said and done all they can to try to avoid the impression that their actions are aimed against Chechnya itself.
''If the army gets involved, this would not mean it would be fighting against the Chechen people,'' Defense Minister Pavel Grachev said last week.
Instead, Dudayev himself is being painted as the crux of the problem. ''The struggle in Chechnya'' pits ''democratic forces'' against ''the lawless fascist regime, and it will continue until the criminal Dudayev clique is destroyed,'' said Bislan Gantamirov, chief of the Chechen opposition to Dudyaev.
Without a quick political solution, however, Russia faces difficulties. Chechen leaders' threats of a prolonged guerrilla war may not be serious because they lack the logistical support and supply lines guerrillas need, but they could certainly make a Russian occupation costly.
''You need more troops to enforce martial law than you do to take Grozny,'' Mr. Felgengauer pointed out. ''In the long run, enforcing martial law would be a problem.''