MOSCOW — Russian Prime Minister Vladimir Putin's decision to seek the presidency in 2012 raises the specter of increased tensions between Russia and the West and the possibility of the former KGB officer remaining in power until 2024.
"Putin's style is very different from [current President Dmitry] Medvedev's — it's more confrontational, more combative and aggressive," said Fiona Hill, a Russia specialist and senior fellow at the Brookings Institution in Washington.
His style was on full display last month, when Mr. Putin accepted his party's nomination for president in 2012.
"There is nothing that can stop us," he told thousands of cheering United Russia party members at Moscow's Luzhniki stadium for a party congress Sept. 24.
Mr. Putin's first stint as president, from 2000 to 2008, saw Russia at its most assertive since the collapse of the Soviet Union, with its navy and air force restarting long-range patrols.
In a 2007 speech in Munich, Mr. Putin accused the U.S. of trying to establish a "unipolar" world.
"The United States has overstepped its borders in all spheres — economic, political and humanitarian, and has imposed itself on other states," he said in a speech that recalled Cold War tensions.
The White House has said it will work with whoever is in power in Russia, but Mr. Putin's return is likely to put the recent Washington-Moscow "reset" under strain and exacerbate differences over U.S. plans for a European missile-defense shield.
If Western leaders are wary about having to deal with Mr. Putin again, there is little doubt that many Russians will welcome his return, as a video circulated on YouTube last week aptly demonstrated.
The first half of the video shows about a dozen Russians complaining about low salaries, corruption, low living standards and other social ills. They are asked, "Will you vote for Putin?" They answer, "Yes," justifying their intentions by saying "He's a man you can trust" and "He cares about the people."
"The Russian people tend to rely more on emotion than logic, and they believe in the greatness of the czar," said Anastasia Markitan, a journalist at state news agency RIA Novosti.
"In fact, most people are entirely ignorant of the ins and outs of the political process and tend to rely on stereotypes, such as 'Putin is a man of action.'"
Mr. Putin has built his strongman image on the widespread perception that he was responsible for saving Russia from the chaos and anarchy of the Boris Yeltsin-era.
But critics say he has stamped down hard on dissent and taken no serious measures to tackle rampant high-level corruption.
"Of course, Putin brought order," Muscovite businessman Pavel Letov said. "But that's about all he did. It's strange that the people are still under some kind of illusion. There's pretty much nothing left that his officials haven't stolen."
Opposition parties say that Russia faces a long, Leonid Brezhnev-like period of stagnation with Mr. Putin's return.
"There won't be any modernization," Sergei Mitrokhin, leader of the opposition party Yabloko, told Radio Free Europe. "There will be a deepening of the tendency toward stagnation that will lead to a crisis in the near future."
But the country's liberal, pro-Western opposition is largely marginalized and lacks much grass-roots support.
Alexei Chadayev, the head of United Russia's political department, hit back at criticism of Mr. Putin's decision to stand for a third term by labeling opposition figures "people who cannot manufacture tanks but like to fight for the driver's place in them."
The procedure for nominating presidential candidates has yet to formally begin, and it is far from clear who might challenge Mr. Putin. But would-be presidential candidate Eduard Limonov said the return of the one-time Federal Security Service chief is, in fact, to the opposition's advantage.
"It's for the best," he said in comments on his Live Journal blog. "Putin is a much more convincing symbol of Russia's problems than Medvedev. He is compellingly unacceptable and unpleasant."
Barred by the constitution from serving more than two consecutive terms, Mr. Putin stepped down as president in 2008 and ushered into power his handpicked successor, Mr. Medvedev, who immediately returned the favor by appointing him prime minister.
Although Mr. Medvedev showed occasional glimpses of independence, it was generally assumed, both at home and abroad, that Mr. Putin continued to call the shots.
A U.S. Embassy cable published by the anti-secrecy website WikiLeaks last year neatly captured the widespread view of Russia's ruling tandem when it dubbed the younger Mr. Medvedev "Robin to Putin's Batman."
Mr. Medvedev put an end to rumors that he might stand for a second term when he told delegates at the congress that they should back Mr. Putin for the presidency.
Mr. Putin, to a standing ovation, accepted. Mr. Medvedev will head United Russia and is likely to switch roles with Mr. Putin after the presidential election in March.
If Mr. Putin triumphs in the polls — and few here doubt he will — recent changes to the constitution mean he will not have to seek re-election for six years, until 2018.
A successful bid for a second term would see Mr. Putin in office for almost as long as Soviet-era dictator Josef Stalin.
The months leading up to the United Russia party congress saw Mr. Putin step up his trademark macho appearances on state TV.
First came a diving expedition in the Black Sea and then a nocturnal ride on a Harley-Davidson through the southern Russian city of Novorossiysk with a bunch of bikers.
While all this was judged to be the start of Mr. Putin's push for the presidency, the timing of the announcement came as somewhat of a surprise. Most analysts had predicted that he would announce his decision to run after December's parliamentary elections.
Analysts have suggested a looming economic crisis — the ruble fell to its lowest rate against the dollar in two years last week — forced Mr. Putin's hand as he looked to assure ordinary Russians and foreign investors that the country is in safe hands.
But with Russia already having lost $30 billion in oil revenues this year, not everyone is convinced that Mr. Putin is the man to reassure investors.
"Many foreign investors really hoped that Dmitry Medvedev would stand for a second term," said Yulia Bushuyeva, managing director of the Moscow-based Arbat Capital investment fund. "They associate Medvedev with modernization, reforms and the fight against corruption.
"Putin's return signals that there is no point in expecting large reforms for potentially the next 12 years," she added.