Amidst the golden splendour of the Kremlin’s Hall of the Order of St Andrew, Vladimir Putin was once again inaugurated as president of Russia this morning. But while today’s event was in many ways a carbon copy of the ceremony that has taken place five times now since 2000, it marks a significant watershed in the history of Putin’s rule: for the first time since assuming power 24 years ago, his leadership can no longer be considered constitutionally legal.