Since the game should be a mix of RPG and simulation there is no any special rule, it suppose to be a simulation of real life. That means, for example, player can't just claim he is a leader of a political party, all adminstrative requirements have to be provided, there have to be adequate number of members to form a party and it have to be registerd at particular state department. It is esential to build all bureaucracy machinery to the possible degree.It is also esential to asure that players have to act in a group if they want to achive some goal.
Another important thing is that the group of players supporting prevalent political oppinion has significant influence on the further development of the game using all available instruments of public diplomacy (first of all through the control of journalists and medias, but also recruiting celebrities for the promotion of their goals, bribing members of the oposition etc.). That way it should be possible to form two or more groups of players strugling to make their oppinion prevalent among the population.
Real simulation requires full 3D interface but since it is an immense job for the begining game could be developed using some text based system.