George R.R. Martin's A Song of Ice and Fire is a political story, and not merely in the sense that its characters are engaged in political conflicts, that those conflicts have been inspired by political history (like England's War of the Roses), or that one might learn tactical lessons from their conduct (which is what seems to have engaged most of those who write about the show's politics). The saga is also political in its having something to say about the world on the page, and to the extent that that world reflects the one in which we actually live, our world as well.
Where a great deal of fantasy, high and low, romanticizes the past in that way critics like Michael Moorcock have long found problematic, Game of Thrones strikes me as a staunchly anti-feudal story. Reading it I am overwhelmed by the sheer creaking, wobbling, arbitrary, bloody instability of a system in which adultery can start a civil war. It may well be that the character of the people in charge makes a difference, that there is such a thing as an honorable lord--but as we see in Eddard's case, their honor does not redeem a bad system. In fact, to the extent that his uprightness makes him insist on the absurd principle legitimizing rulership in Westeros (lineal succession), his honor not only costs him his life, but does much to set the seven kingdoms ablaze.
In its depiction of that blaze, Martin's saga is also an anti-war tale, keeping the reader ever conscious of the brutality and brutalization that follow in its wake. In the first volume Martin seems unable to muster much enthusiasm for Robb Stark's bid to become the King in the North, and for good reason, that quest soon enough proving foolish. We see the men of the Night's Watch driven to and past the breaking point, and turning on their commander and their hosts when they snap. We see what the contending armies do to the countryside as Brienne and Jaime and Arya journey across the desolate Westerosi landscape--Martin's depictions of which are some of the most powerful anti-war writing I can remember encountering in popular fiction in recent decades. And while this is not a story told from the bottom up (our cast of characters are generally the elite of the elite), we never forget that the bottom exists, or how it suffers through it all--life in Flea Bottom certainly bad during the siege of King's Landing, but never really good, even in those times when court poets and gentleman historians write of good kings on the throne bringing peace and prosperity to the land.
Such things come through less forcefully in the show. It may be the case that this is deliberate on the part of the show's makers--but it may also be a reflection of the show's format, the focus on the progress of the main storylines (which have the episodes zipping among a handful of viewpoint characters), and the material limitations of a television production in comparison with a film epic, constraining the series' effect in these respects.
My Posts on Game of Thrones/A Song of Ice and Fire