By Catherine Belton
Dmitry Medvedev, Russia's president, broke a taboo on constitutional change yesterday when he asked parliament to extend the presidential term from four to six years - a move that could pave the way for Vladimir Putin to return as head of state for a further 12 years.
Mr Medvedev used his first annual state-of-the-nation address since taking over from Mr Putin this year to deliver a threat to deploy missiles in Russia's Baltic enclave of Kaliningrad, in response to US plans to base a missile system in Poland and the Czech Republic.
He spoke at length of the importance of the Russian constitution in protecting democracy and individual freedom.
But he dropped a bombshell by saying the constitution should be "corrected" to allow Russian presidents to serve longer terms.
Presidents are limited to two consecutive four-year terms, but can return to power after a period out of office. When Mr Putin was president, he rejected calls to change the constitution to allow him to remain in power, insisting that he could not alter a cornerstone of Russia's democracy.
Mr Medvedev said that extending the term of office was necessary to help Russia's transition to democracy.
A Kremlin official said the proposals would not apply to Mr Medvedev's current term. This was seen by analysts and opposition figures as a signal that Mr Putin, the current prime minister, could be preparing to return to the presidency.
"This is the strengthening of the current authoritarian regime," said Vladimir Ryzhkov, who was an independent member of parliament until changes to electoral laws saw him lose his seat last year.
"This was a clear signal that the current regime of Putin and Medvedev intends to further strengthen its power and deepen its grip over the country."
Mr Ryzhkov said other moves announced by Mr Medvedev to broaden political representation were "cosmetic changes".
"This is an imitation of democracy," he said.
Any change in the limits to a presidential term needs approval by both chambers of parliament, which are dominated by backers of Mr Medvedev and Mr Putin.
Vyacheslav Nikonov, a Kremlin-connected political analyst, gave warning that a review of the constitution for the first time since it was written in 1993 could open "a Pandora's box" of changes.
Mr Nikonov and Sergei Markov, another Kremlin-connected political analyst, said the announcement was a surprise. But others said they thought it had been in the works for some time.
Olga Kryshtanovskaya, an analyst with the Russian Academy of Sciences, said: "This was all planned a long time ago. This opens the way for Putin to return to power for 12 years and rule up to 2024."
Mr Ryzhkov said Mr Medvedev could use the financial crisis as an excuse to stand down next year, clearing the way for Mr Putin to return.
Mr Putin's ratings are much higher than his successor's, and there has always been speculation that Mr Medvedev could step down to allow Mr Putin to return to power.
Mr Putin's spokesman, Dmitry Peskov, defended the proposal, saying it would not require a referendum - which would imply a fundamental constitutional change - but only needed backing by a parliamentary majority.