In this way, fantasy as a genre seems to have an almost unfair advantage at allegorically chronicling our age. Elsewhere, the crudeness and savagery of modern life are artfully encoded in the palm-sweating desperation of the meth-dealing dad in “Breaking Bad,” the terse detachment of the pill-popping mom in “Nurse Jackie” or the quiet machinations of the enigmatic assassin in “Dexter.” But that brand of darkness has so thoroughly become the default syntax of cable dramas that even these sensational figures can’t quite jar us out of our somnambulant state. We apparently require gigantic walls of ice, supernatural wolf puppies, gory jousts, dragon eggs and a nomadic warrior who looks like Dave Navarro after heavy steroid use. Maybe it takes the grand scale of sybaritic kings and imaginary kingdoms to do justice to the perversions and the nihilism of post-empire America.

And so, by blending together Dungeons and Dragons porn fantasy with the wanton violence and menacing civic leaders of “Deadwood,” “Game of Thrones” offers an alternately hedonistic and bleak tale in which constant suspicion is just one of the ugly traits necessary to survive the darkest of times. When Lord Stark (Sean Bean) thanks King Baratheon (Mark Addy) for honoring him by naming him the Hand of the King, Baratheon replies: “I’m not trying to honor you. I’m trying to get you to run my kingdom while I eat, drink and whore my way to an early grave.” (Roger Sterling of “Mad Men” couldn’t have said it better himself.)

Baratheon, it turns out, is an apt reflection of our modern condition. Like Don Draper on a drug-fueled weekend in Vegas or Tony Soprano on an average afternoon at the Bada Bing, Baratheon has a gruffness that only thinly conceals his despair, and his dissatisfaction and longing are most palpable when he’s gamely mimicking the indulgences of his glory days. The joyless gluttony of fallen romantics feels pretty timely at the moment, particularly when kingdoms seem likely to rise and fall based on their whims. But it also highlights the ways “Game of Thrones” embodies the illuminative possibilities of fantasy yet displays a stubborn adherence to the genre’s knee-jerk conventions — a stubbornness that ultimately prevents the show from fully transcending its birthright.

Fantasy, for all its imaginative potential, is fertile ground for nihilists. This can be useful. For one, it enables its writers to personalize viciousness in ways that could never be accomplished in contemporary realism. When, on “Game of Thrones,” a princess begs her brother not to force her to marry a savage whose language she doesn’t understand (a situation not unfamiliar to your average single female), he coldly informs her that he would let the entire savage tribe have its way with her if that might restore him to power. (“All 40,000 men and their horses, too, if that’s what it took.”) When the queen’s son tries to convince her that a rival clan is their enemy, she spits, “Everyone who isn’t us is an enemy.” By repositioning a familiar message — “If you’re not with us, you’re against us” — in medieval-fantasy terms, the show’s creators force us to view its ghastliness with fresh eyes. In contrast to the uneasy alienation of dropping bombs on countries thousands of miles away, “Game of Thrones” presents its carnage in such extreme close-up that it can’t be ignored. Heads are sliced off with stunning regularity, innocents are harmed or killed without much hesitation and the camera lingers lovingly on each surge of blood. (Unfortunately, it can be a struggle to take such gratuitous gore seriously, resembling, as it so often does, a particularly bloody Monty Python skit.)

And then, of course, there is the looming threat of winter. Apparently seasons can last a decade in these parts, and winter will usher in around-the-clock darkness and invasions by the deadly creatures who live north of that aforementioned gigantic wall of ice. Even commoners in “Game of Thrones” tend to distinguish between people born during the summer and those who are old enough to recall the terrors of the last winter, echoing what was once said of Vietnam and World War II. With the dark season approaching, everyone in Westeros — even decadent King Baratheon — is growing more anxious and depressed about what the future might hold for them.