Can an action film also be a work of art? That's one of the questions raised by The Bourne Ultimatum, Paul Greengrass's third installment in the thriller series starring Matt Damon as Jason Bourne, an ex-assassin on a mission to discover a personal history obliterated by amnesia and clouded by years on the run. Bourne's past memories are fragmentary; his present-tense instincts are rock-solid. He can't tell you his real name or hometown, but he can field-strip a gun without looking at it, find a way out of any trap, hotwire a car with less effort than it would take the owner to find, insert and turn the key. But these killing skills can't get him to the center of his shattered life -- who he was, what he did.

And The Bourne Ultimatum does have elements of art: Political and social resonance, visual and linguistic symbolism, references to the world the films have shown us and the world outside of it, rich characters with fully-developed personalities. It also has all the elements of the modern action thriller -- how'd-they-do-that stunt work, crazy-fast fight action, tautly-wound scene construction that culminates in moments that leave you breathless. The Bourne Ultimatum picks up precisely where The Bourne Supremacy (also directed by Greengrass) left off -- Bourne, wounded and alone, is in Moscow. He's just atoned to the daughter of two of his victims -- killed not in the name of national security or the public good, but rather for private gain. Bourne's work was a secret -- but Simon Ross (Paddy Considine), a journalist for The Guardian has been running pieces about Bourne's work and Treadstone, the black ops group he worked for. Bourne would like to know who Ross's source is. So would the people who are trying to re-start Treadstone under the new name Blackbriar, to make it "... the sharp end of the stick ..." in America's arsenal.

Greengrass has said of the Bourne films that " ... there isn't a bad guy -- there's a bad system." In Ultimatum, the system's personified by Noah Vosen (David Strathairn), the sort of cold-blooded CIA technocrat who orders " ... the heart-healthy omelet with goat cheese and peppers ..." before heading into the office to order the deaths of civilians. Pamela Landy (Joan Allen), the lesser of two evils, asks Vosen about his suspect methods: "You go down this path, where does it end?" His response wouldn't be out of place in the real world: "It ends when we win." Allen and Strathairn don't exactly get to shine as actors in these parts, but their experience translates on-screen, bringing grit and gravity to what lesser actors would have rendered as caricature.

Bourne is being tailed by other CIA "assets" -- which is a nice way of saying "killers." They may not have his skill set or natural reflexes, but neither do they have his compunctions slowing them down. They're known by their surnames -- Desh (Joey Ansah), Paz (Edgar Ramirez) -- and they do not hesitate. The Bourne films have always had astonishingly well-constructed fight scenes, and Ultimatum does not disappoint in that regard -- there are sequences here full of breathless tension as two people, highly competent and unwilling to die, claw and strike at each other in small rooms that one of them will not leave. Part of the appeal of the Bourne character -- consistently and superbly underplayed by Damon -- is that he's a man who's fighting fiercely for a brand-new life, because he's discovered how much there is to lose. (Interestingly, there's a brief hint at another aspect of Bourne's past with another series supporting character that's -- wisely - not explored; you're given as much information as Bourne is, and the film leaves it at that.)

Visually, the Bourne films under Greengrass have come to possess their own grammar -- a constant, rigid sense of look and feel. (And, to be fair, much of that springs from Doug Liman's excellent work on The Bourne Identity.) Cameras are mostly hand-held, which some see as immediate and exciting and others find distracting; the lighting is naturalistic, streetlamp glow and fluorescent blur. Nothing gleams in Bourne's world; every location looks real; we don't see the action from the perspective of a soaring God-like camera but rather (mostly) from the street-level view of the participants. It's the kind of 'natural' it takes an incredible amount of skill and artifice to craft, and it lets Greengrass and his crew recapture the action film from the antiseptic, pixilated gleam where Hollywood embalmed it in and drop it, vulgar and squalling, into the vibrant, dirty world we all live in.

We finally see some of how Bourne became Bourne in Ultimatum -- including a brutal program of psychological conditioning, as Bourne's hooded and "waterboarded," breaking down the man to rebuild him as a weapon. Some audience members will feel queasy at the thought they've paid money at the box office to witness this violent fiction; then again, they've already paid tax dollars to support the same thing in reality. The Bourne films may be exciting and propulsive, but they're also critiques -- of an intelligence apparatus gone mad with power, of the people who let that happen, of the broken contract between warriors and leaders. Bourne is told by his creators during his training that "Your missions will save American lives." Yet all Bourne did was kill -- in the name of power, or money, or to cover up embarrassing policy failures. It's a blunt metaphor for what's happening in the real world, as troops have tours of duty extended in Iraq, and soldiers and civilians both suffer and die so that the dignity of our leaders might be maintained, so that all the death and pain that's come before won't be seen as a failure or an embarrassment for the people who demanded it.

But these thoughts come to you later on; in the theater, The Bourne Ultimatum holds you in a fierce grip that gleams with the sheen of sweat and effort, dragging you across the globe from hazy winter shades to sun-drenched streets. The action is even more fiercely cut than in Supremacy, which can be distracting -- now and then the tempo and number of the edits obscures the simple visual mechanics of what's happening when and to whom. And Ultimatum features several plot howlers worthy of a Roger Moore Bond film -- does the CIA really put the address of its ultra-secret domestic operations program on the cover sheet of briefing books?

The other self-contained drawback to Ultimatum is that Bourne's struggle is a personal one; there's no ticking clock. We're told that Blackbriar is bad (a dossier on the program contains several sheet of confirmed targets, each stamped both "Terminated" and "American Citizen" -- a ludicrous design touch, as if the nationality of the victim makes state-sponsored murder even worse), but it lacks the sort of counting-down urgency that we've become used to in action films; then again, maybe that's the point. The final moments of The Bourne Ultimatum take us full-circle to the themes, characters, dialog and visuals of the first film, and some might take that as a possible starting point for Bourne to return. I'd rather not see that happen -- about all that's left for Bourne to do is parkour his way into the White House and start re-writing intelligence policy, or slump into lazy conventions and cliche's.

What Greengrass has done with The Bourne Ultimatum's visual and contextual return to the beginning is close the series, to me -- leaving all the bigger questions and underlying themes still laying uneasy on my mind long after the adrenaline rush of shattered glass and bruised flesh has worn off. I don't know that if an action film can, in fact, be art -- but I do know that The Bourne Ultimatum has stuck with me, and will stick with me, in ways that will linger for a while. That's much more than most 'summertime entertainment' does; it's more than most end-of-year would-be Oscar contenders do. The Bourne Ultimatum makes your heart and mind race, and while I'm not certain if the film is art, it's definitely far more than just 'entertainment.'