Prime Minister Vladimir Putin, a former spy who was virtually unknown four months ago, rose to power as Russia's acting president today having pledged to end Russia's precipitous decline and restore the powers of the state as the guiding force in society.

His elevation gives his already formidable presidential candidacy a significant boost in elections now expected in March. After launching the war on the breakaway region of Chechnya shortly after his appointment as prime minister in August, his popularity soared among a public hungry for a strongman. From today on, the resources of the presidency to dispense favors and money, to make and break careers, are at his disposal.

Through all his ideas run a common thread: the need for powerful authority in Russia. Liberal ideals of individual liberty and initiative are secondary to him. The late Deng Xiaoping of China or Chile's former dictator Augusto Pinochet seem apt leadership models for Putin.

"Among us, the state, its institutions and structures have always played an exclusively guiding role in the life of the country and the people. A strong state for Russians is not an anomaly, not something that must be fought for or against, but on the contrary is the source and guarantor of order, the initiator and driving force of all change," he wrote in a statement issued last week, during a meeting of Unity, a successful new parliamentary party that supports him.

"Russia will not soon become, if ever, a second copy of, say, the United States or England, where liberal values have deep historical traditions."

Today, he said Russia's foreign policy will continue to stand on three pillars: equal rights, cooperation and promotion of a "multipolar world," code for opposing the expansion of American influence.

His words have struck a chord with Russians, though Putin is far from the first politician to exploit the desire for order. The extreme nationalist Vladimir Zhirinovsky, retired Lt. Gen. Alexander Lebed and Yevgeny Primakov, one of Putin's predecessors as prime minister, have enjoyed wide popularity based on a shared image of firmness.

But only Putin, 47, applied an iron stick to a national problem: Chechnya, the separatist region in the Caucasus that Putin blamed for everything from terrorist attacks on apartment buildings in Moscow and elsewhere to the crime wave across Russia. This autumn's invasion of Chechnya--which seeks to reverse the result of a war in which Russian forces were ousted three years ago--has been wildly popular.

"It seems to me that Putin responds to the certain deficit that has been formed in the public mind, which is a wish to see effective power, an effective politician," pollster Georgi Satarov said recently. "Chechnya was a way to demonstrate effectiveness."

Putin honed his image by projecting vigor. Television broadcasts showed him making judo moves and donning a flight suit to take a ride in a Russian air force jet. His sandy hair, foxy eyes and lean face contrasted sharply with the jowly look of old-style Soviet leaders and aging Russian politicians, including Boris Yeltsin, the man he replaces.

Putin's admired toughness has not been applied to other troubled areas of Russia's society: corruption, tax evasion or crime. And Russians may wonder where Putin will lead them other than to war in Chechnya. "For Putin," wrote the Sevodnya newspaper recently, "any coherent economic policy is a mirage."

In his inaugural speech to parliament in August, Putin laid out only vague plans for the economy. He said tax policy must be revised to reduce the burden on businesses, and black market commerce must be crushed. In foreign policy, he said his main task "is to raise Russian prestige."

With his law-and-order stance, Putin, a KGB spy for 16 years, seems less the heir to Yeltsin than to Primakov, another longtime KGB operative whom Putin replaced as Russia's most popular politician.

Putin, like Primakov, is a child of the perestroika years of economic and political reform in the Soviet Union, as seen through the eyes of the KGB, which had identified the widening gap between the West and the Soviet Union. "The KGB in Putin's time was very sophisticated on economic matters, more so than any liberal in Russia, without the personal political passions," said Evgenia Albats, a journalist and expert on the KGB.

Putin was well-placed to observe the process. As a KGB agent in the 1980s, he was based in Dresden, Germany, at the edge of burgeoning Western Europe.

In 1989, he was sent to his native Leningrad (now St. Petersburg), although what his exact role there was is not clear. Detractors say he was monitoring economic reformers. He left the KGB in 1991, according to the Sevodnya newspaper.

Putin had made connections with economic liberals and became a key adviser to Anatoly Sobchak, a law professor who was elected mayor of St. Petersburg in 1991. Eventually, Putin was named deputy mayor. When Sobchak was defeated for reelection in 1996, Putin resigned. Opponents of the pair accused their administration of corruption and of owning mansions in France. His political career was rescued by Anatoly Chubais, another St. Petersburger and a favored Kremlin insider, who invited him to Moscow. Pavel Borodin, the Kremlin's controversial property manager, gave him a job.

In May 1998, Yeltsin named him deputy chief of the Kremlin staff, and just two months later, to head the Federal Security Service, a successor to the KGB.

Putin's appeal to liberals, many of whom support him for president, seems to lie in his rhetorical support for democracy. "If we really want to put up an insurmountable barrier to the dark past," he said in a speech last year, "all possible support for new Russia's democratic institutions is the only guarantee."

His liberal credentials were severely tarnished by his inconclusive investigation into the assassination of Galina Starovoitova, a St. Petersburg democrat gunned down on her apartment doorstep in November 1998.

He also showed he knew how to play hardball politics. Last spring, in the heat of a major corruption campaign against associates of Yeltsin, a damning videotape was broadcast on television that purported to show the anti-Kremlin chief prosecutor, Yuri Skuratov, frolicking with women in a Moscow apartment. Putin, in an unusual practice for an intelligence chief, went on the air to proclaim the tape's authenticity. Putin's performance was regarded as a stepping stone to the Kremlin, because he had shown the foremost quality admired by Yeltsin: loyalty.

Today, Putin's first act as president was to order "security guarantees" for Yeltsin and his family.