Kathryn Bigelow deserves credit for many, many things about her tremendous military thriller "The Hurt Locker," but she'd be the first -- and probably the gladdest -- to admit that the simple fact of her gender isn't one of them. That didn't stop multiple media commentators from sanctifying her as some kind of poster girl for "anything you can do, I can do better"-style feminism in Hollywood, as if a woman could only direct a stone-cold action picture as a reproach to the men who handle most such fare, and not merely because it's what she's good at -- and has been good at for over 20 years.  

Bigelow bore this unsolicited symbolic weight with patient, if seemingly weary, grace all the way to the Oscar podium, offering multiple polite statements to the effect that she's not so much a "woman filmmaker" as a woman who makes films, and refusing the Academy's unspoken invitation to turn her history-making Oscar acceptance speech into a self-aggrandizing soapbox stand.

If Bigelow was ever going to express her irritation over this, it was going to be in a tacit manner -- and it's tempting to imagine that she's done so with her quite breathtakingly proficient follow-up "Zero Dark Thirty," in which another unflappable female professional in a male-run environment coolly shrugs off the collegial curiosity prompted by her having a vagina. Tempting, I say, though probably not correct: Bigelow, together with "Hurt Locker" writer Mark Boal, has matters of greater historical urgency and consequence on her mind in this exhaustively charted, imposingly realized procedural -- matters that, if recent political outbursts over its journalistic veracity are any indication, will this time make Bigelow's gender the secondary concern it deserves to be.

At 157 moist-palmed minutes, "Zero Dark Thirty" manages the curious feat of seeming both aggressively terse and well-nigh as long as the 10-year quest it covers: the CIA's protracted, irregular and finally successful hunt for Osama bin Laden, led by a terrier of a female analyst whose devotion to the cause may not be entirely rational, even when ultimately rewarded. 

If the film is often daunting, even oppressive, in its academic magnification of bureaucratic nuts and bolts, that's surely the point: every official detail that keeps us from the rattling, shattering climax we at least know is coming is equally a barrier between the protagonist and the prey she fears may never be hers. No other film since "Zodiac" has so vividly essayed the exquisite ennui of obsessive investigation; our fictionalized heroine "Maya" may reach the practical (if not psychological) closure denied Jake Gyllenhaal's Robert Graysmith, but it's a bleak, antisocial triumph to the last.

It's this overriding atmosphere of nervous fatigue, occasionally dipping into threadbare despair, that makes it hard to square with detractors' accusations that the film "glorifies" torture, even as it does impassively note the occasional effectiveness of the technique: for any audience, the early interrogation scenes are the most viscerally disquieting in a narrative where every victory is written, performed and scored with more than half a mind on its hollow center. If "Zero Dark Thirty" is glorifying any US military procedure, then why does the final raid on bin Laden's lair, for all its pummelling technical brio, feel the precise opposite of rousing as it casts an unwavering eye over sundry cruel casualties en route to the man himself?

"Zero Dark Thirty" follows "The Hurt Locker" in attempting to portray the realities of war without politics, this time largely from the office rather than the field; as a journalist, Boal seems as interested in the means as he is in the end. Perhaps he's written something of himself into the character of Maya, a clinically dour redhead who seems preoccupied with process and suspicious of payoff -- a sister figure of sorts to James, the dispassionately adrenalin-chasing hero of "The Hurt Locker."

As played with a milky-hard stare and a flinty drawl by the increasingly remarkable Jessica Chastain, Maya betrays no more profound emotional investment in her search for bin Laden than she seemingly would in any competitive game. She badly wants to win, and she's neither too proud nor too polite to let her superiors know that, but if there's a more personal stake in this revenge story -- beyond the lingering national grief alluded to in the risky but respectful sonic montage of 9/11 victims' doomed cries that opens the film -- she keeps it buttoned tightly beneath her black pantsuit and impenetrable Ray-Bans.

The mostly unjudging eyes behind them serve as our own for the bulk of the film; it's telling that even they show a flicker of doubt when first introduced to the grotesque torture methods employed by her government, as a near-defeated victim appeals to her womanly compassion; "You can help yourself by being truthful," is her typically blunt reply. An eleventh-hour display of genuine emotional release from Maya is moving, but Boal, Bigelow and Chastain conspire to make us uncertain as to whether she's mourning a personal or professional lack. 

"Zero Dark Thirty" may ostensibly unfold as a hardline, semi-factual procedural in the "All the President's Men" mold, but it fascinates most as a character study of a virtual anti-character. As Maya's cypher-like qualities are placed in ever sharper relief against more vital, vulnerable personalities like fellow agents Dan (Jason Clarke, beautifully tracing the film's most quietly full character arc, from hothead to human ally) and Jessica (a brilliant quick-sketch characterization from Jennifer Ehle, her bruised warmth too fleeting a presence), our questions over the motivations behind her passivity continue to brew.

Bigelow, meanwhile, serves these characters best by holding them at arm's length, often literally so as she and cinematographer Greig Fraser repeatedly strand Maya in chilly long shots. Her visual and sonic architecture here, often recalling the brooding, half-lit sleekness of "Insider"-era Michael Mann, is a long way from the propulsive, on-the-spot vigor of "The Hurt Locker."

The alliance with Australian DP Fraser, a deft magician of daylight in such films as "Bright Star" and "Killing Them Softly," is key to the film's sustained, somber atmosphere: even the heart-in-mouth midnight raid, astonishingly tense as it is, takes on an elegiac quality under his lens, aided no end by the militaristic orchestral syncopations of Alexandre Desplat's superb score, his richest and most unnerving since "Birth." Though it seemed from a distance a return to the physical and psychological territory of "The Hurt Locker," "Zero Dark Thirty" finds Bigelow working with bold new tools and textures, asserting herself as a masterful observer of talk and action, her gaze as keen and unblinking as that of her distant protagonist.