Short answers, pulled from the story.
Vladimir Putin stepped down as president on the 7th of May 2008. He assumed the role of prime minister under President Dmitry Medvedev following constitutional limits preventing a third consecutive term.
Political analysts coined the word tandemocracy during this period to describe rule by two leaders. Political scientists Gleb Pavlovsky and Stanislav Belkovsky discussed future configurations before the 2008 election that led to this terminology.
In January 2009 only 11% believed Medvedev controlled Russia according to Levada Center surveys. Thirty-two percent thought Putin was the true leader while half of respondents said both shared actual authority.
Western media and foreign diplomats debated the nature of this partnership with varying perspectives. The Financial Times reported global concerns regarding Medvedev's role while former German Chancellor Gerhard Schröder claimed both leaders addressed problems together in friendship.
The constitution proved immensely pro-presidential while granting limited oversight powers which ensured stability but reduced accountability mechanisms. The president lacked authority to question ministers or the government and the Duma similarly could not challenge its leader's cabinet.