The great Russian writer, Fyodor Dostovesky, was one day away from being executed when he was released from prison. Voltaire was expelled from France for his views; the great Transcendentalist Ralph Waldo Emerson had crowds following him from town to town. And, it is a known fact that social reforms were effected after several of Charles Dicken's writings and lectures. These facts seem to underscore the statement that literature does shape politico-structures.
I think you should find out if you have to agree with the statement or if you are allowed to disagree with it. Given the choice, I would disagree.
One way or the other, you should look at instances where literature might have influenced sociopolitical structures. For example, you might look at the impact of Uncle Tom's Cabin on pre-Civil War America. You must then look at how/whether that work affected the sociopolitical situation or whether it simply reflected it.
I would argue that works like that act as catalysts for attitudes that already exist.
I think that there are many avenues to pursue with such a topic. I would say that there are some challenges present within this essay. The formation and shaping of socio- political structures is influenced by many different elements. Literature might be a part of this. Works like Dickens' Hard Times might represent literature that brings awareness and helps to develop consciousness regarding socio- political structures. The works of Karl Marx and Adam Smith might be examples of work that helped to create both an economic and political structure that resonates in our intellectual sensibilities in the modern setting. The Enlightenment thinkers such as Voltaire, Rousseau, and Montesquieu wrote literature that ended up shaping the modern democracy, something that has become a permanent part of our world. Along these lines, Jefferson's writing of The Declaration of Independence helped to form the basic premises and ideas of the American nation state. Finally, work by writers like Upton Sinclair's The Jungle went very far to shaping the notion of the modern consumer standing against a business operation that is driven by the sole ends of profit.