What is the purpose of government?

The purpose of government at home is to manage and protect the affairs of the dominant class in society by governing 'over' the citizenry to this end to enable the exploitation of the vast majority by the parasitic ruling class in the interest of profit . This is done using both ideological state apparatus, and repressive state apparatus. This is true regardless of the political hue, conservative or liberal, of the government. This is true also regardless of the forms of capitalist ownership of the means of producing and distributing wealth. production, whether private, corporate or state owned.

 From time to time governments may adjudicate over the affairs of the domestic capitalist class, when conflict arises, financial capital versus industrial, service economy versus agribusiness. Small busines versus big business and so on. One persons 'levelling of the playing field' is anothers 'regulationary infringement' upon legitimate business.
Abroad the purpose is the same to protect, steal and pursue and invade in the interests of the nation state, conditions for gaining markets, raw materials and combining in spheres of geo-political advantage to those ends. War is business by other means just as it is politics also.
Both poverty and war are inevitable concomitants of capitalism.

 The nominal freedom of the citizenry as to appearing to have power by the ballot, just amounts to the freedom to be 'governed over' in the interests of the parasite class. 

The illusory choice is that between Tweedledee versus Tweedledum.