Putin made his announcement during a speech to the pro-Kremlin Unified Russia congress.
"If our people, Russian citizens, give their vote of confidence to Dmitry Medvedev and elect him the new Russian president, I will also be ready to continue our joint work, in this case as chairman of the government of the Russian Federation -- without any changes in the [balance of] power between the presidency and the government," Putin told cheering delegates.
As the Kremlin's candidate, Medvedev is widely expected to easily win the March 2 election, which analysts say will more closely resemble a coronation -- the passing of power to a carefully considered, unthreatening political heir.
"Today the situation has finally been clarified," says Olga Kryshtanovskaya, head of the Center for Elite Studies at the Russian Academy of Sciences Institute of Sociology. She adds that while Medvedev will be the de jure head of state, Putin will rule de facto.
"It will be the sort of tandem in which Medvedev will fulfill more ceremonial and decorative functions and Putin will make the key decisions," Kryshtanovskaya says.
But while Putin's announcement clarifies which post he will occupy after a new president is inaugurated in May, uncertainty still looms over how Putin will remain in charge when he leaves the Kremlin.
"He is in a zone of risk. [Putin] is doing everything so he will not be a lame duck -- or a lame bear," Kryshtanovskaya says. "All the intrigue, all the secrecy [surrounding the succession] was all designed to draw attention to this process so it would not be visible that he is taking risks and that he is vulnerable."
Means Of Control
Kryshtanovskaya and other Kremlin-watchers say Putin will partially rely on Medvedev's loyalty to maintain control over the political system, but also will use other levers of influence.
One such lever is Putin's control over the Unified Russia party, which on December 2 won a two-thirds majority in the State Duma. That majority is enough to initiate constitutional amendments -- and to impeach the president.
Putin is also expected to maintain at least informal control over the military, security services, and Foreign Ministry -- which under current legislation report to the president.
And despite Putin's pledge not to decrease the president's powers at the expense of the prime minister, analysts nevertheless say constitutional changes are likely.
"This tandem will hardly last the whole four-year presidential term without changes" in the balance of authority, Kryshtanovskaya says. "I think the process of amending the constitution will soon start. At first it will be just discussions. Later a Constitutional Assembly will be convened. This is a long process. The goal will be to change the political system."
Another possibility, Kryshtanovskaya says, is for Putin to return to the presidency after a respectable interval with Medvedev in office. The constitution only forbids presidents from serving more than two consecutive terms.
Putin anointed Medvedev -- who currently serves as first deputy prime minister and chairman of the state-controlled natural gas monopoly Gazprom -- in televised Kremlin meeting on December 10.
Putin said he "completely and fully supported" Medvedev's candidacy, which was put forward by United Russia and three other pro-Kremlin parties. The next day, Medvedev, also in televised comments, appealed to Putin to serve as his prime minister.