FACTBOX-Putin's succession options

(Reuters) - The victory of President Vladimir Putin's United Russia party in Sunday's parliamentary vote marks the first stage of a planned transition of power, due to be followed by presidential elections on March 2, 2008.

Putin, who is due to step down after the presidential polls, has promised not to change the constitution to allow himself a third consecutive term. But he has made clear he wants to continue controlling the levers of power after his departure.

The following are several possible scenarios for the Russian succession considered by analysts:

FAIR PLAY

According to one theory, Putin will pick a close ally with a strong government background as the preferred candidate in order to guarantee that his policies will be followed.

Putin will then step back, exercising his influence at a distance and perhaps preparing for a fresh presidential bid in 2012, which is allowed by the constitution.

Kremlin-watchers see first deputy prime ministers Sergei Ivanov and Dmitry Medvedev, Putin's loyal lieutenants and his close friends, as possible candidates.

The disadvantage of this option is that in Russia, where the president enjoys sweeping powers, any informal influence Putin might try to exercise is unlikely to last. The next president may sideline him quickly and stop him from returning.

PROXY PRESIDENT

Another theory is that Putin, whose popularity and administrative powers give him a decisive say in who succeeds him, may deliberately pick a weak and old political figure to become president. This would allow Putin to retain a strong power base and rule from beyond the Kremlin walls.

Potential candidates for a proxy president include Prime Minister Viktor Zubkov, the head of the United Russia party and State Duma speaker Boris Gryzlov, and the head of the Federation Council (upper chamber) Sergei Mironov.

Fuelling speculation about such a possibility, Putin has hinted he could become prime minister. He could also become Duma speaker and majority leader, controlling enough votes to overcome any presidential veto and rewrite the constitution.

Or he could take over Russia's Security Council.

The problem with this option is that Putin will have to initiate a dramatic redrawal of the balance of power to make these positions influential enough to dictate policy to the president. This would mean violating his own promise not to change the constitution.

AN EARLY RETURN

Some experts suggest that the option of a proxy president could be just a prelude to Putin returning to the Kremlin.

The constitution bars him from running for a third consecutive term. But he could stand again in the next polls in 2012 -- or even earlier, if the president elected next March resigns early.

Putin's allies have even pointed out a legal loophole which may allow him to stand in the March 2 election if he quits early as president to head the Duma, after leading the United Russia's successful election campaign.

(Writing by Oleg Shchedrov; Editing by Richard Balmforth)