First off all, what is the State? Max Weber says that the state consists of an entity with a "monopoly on the legitimate use of physical force within a given territory".
Others would specifiy that the State refers to a set of governing institutions that derive authority from a specific mandate (whether that be God, the tip of a sword, or the 'will' of the people). The degree of influence exercised by the state may vary by example. The Egyptian Pharoah for example, exercized a more direct influence on the economic affairs of his State than does modern America (ie. through slave workers), but the latter has a more broad role in defining and regulating society (ie. legislation surrounding lifestyle choices).
Some say that the State is derived from civil society, that organized existence naturally leads to a system of governance and organization (eg. Hobbes or Kant). Marxists sometimes draw no distinction between society and State, while anarchist thinkers argue that civil society can function without an athoritative state altogether, and that it's existence is as unfortunate as it is unecessary.
Our contemporary is governed my overlapping institutions of power, but the primary set of blocks take the form of sovereign States that (generally) recognize eachother, whilst awknowleging individual supremacy (taking into consideration the degree to which States like Russia, France or the US readily interfere with the domestic affairs of foreign (nation)States).
Most importantly, while it has its critics, the legitimacy of the State is recognized by nearly all members of modern 'Democracies' and authoritarian regimes alike, while the instruments of media, education, and the economy are often hard to seperate from it.
Though Michel Foucault questioned the relevance of the State in it's centralized Westphalian interpretation, it is clear that potent power is still exercized in the name of sovereign government, and that the interlinking channels of power do still run through institutions connected with the WHite House, Downing St., etc.
So what do you think? Is the role of the State legitimate? Is the social contract a legitimate justification? What about God? What about the defense by results? (That without the state we would just be worse off) If not the State, then what?
:)