Personally, I firmly believe that the State should largely seek to implement negative freedoms as described by Blacktide.
I do not think it should be a state's prerogative to go and try modifying the society which it is meant in the first place to protect.
I think the entire purpose of a state is to act as the strong arm which serves its inhabitants by protecting them from harm via a monopoly of force.
The ideal state in my mind is one which has the power to protect its inhabitants from any foreign or domestic threat, but does not seek to change the society itself. I think it is the job of private persons to build their own culture and economy.
In fact my perfect world is one in which there is no need for a state at all. A world where each person respects the rights of others, and works out their problems peacefully.
This is exactly why post-modernism or liberalism had became conservative and left its revolutionary role. You view current society as a natural manifestation of humanity and seek to find mechanisms that will preserve what we have as its the natural law of things. What you are not considering is that, "preservation of society", in itself is an ACTIVE role...no matter how much you claim to distance from manipulating society, just by preserving the existing order, you are "enforcing" something upon it.
New generations that are born into this take everything for granted unless they study....alternatives are just intellectual arguments that carry no meaning. This is an inherently conservative stance, EVEN if society we are talking about is highly -free- by our current standards.
That is because our standards are shaped by social norms which are in return shaped by society we are born into.
Long story short, I doN't believe there is a natural social order...there is only what we make of it. And belief in a natural order where state only maintains what exists is delusional. Each centralized nation state with its constitution and laws schools and taxation represent a structure which constantly&ACTIVELY reproduces itself.