Who needs tuxedoes, shaken-or-stirred-it-doesn’t-matter martinis and ridiculously drawn-out poker games when you’ve got Jason Bourne? He represents a new era of spy movie, one fitted for our dark age of war and big budgets. There is no girlfriend of the evil boss to steal away, or casinos to look suave in. In fact, there isn’t a single witty remark at all; Matt Damon, the title character, is dead serious for two hours straight. And we love him for it.

“The Bourne Ultimatum” is the third, and most likely final, installment in the Bourne series, based on books by Robert Ludlum. It’s hard to say for sure, though, as the first two films both had neat, comprehensive endings, and look where we are now. Damon commented in an interview that it would be hard to make a fourth, considering the lack of an available plot, and he’s right: after three films, there isn’t much Bourne left to cover.

This installment is the most straightforward. A semi-amnesiac after being thrown into the water after an aborted mission in the first film, Bourne remains haunted by his past, which he can never quite resolve. He wants to find his true identity, to know where he came from, to return to his pre-superagent self. In order to do so, he has to kick a lot of ass around the world, including most Western European capitals, Africa and New York City. Directed by Paul Greengrass, who also directed the overdone second Bourne movie, “The Bourne Supremacy,” this film shares all the hallmarks of the Bourne films — very quick cuts with the camera, a fast-paced, drum-heavy score, CIA bureaucrats in rimless glasses barking out orders, blurry flashbacks and incredibly elaborate car chase scenes. They’re all here, alive and well.

There is no romantic intrigue in this one, despite the presence of Julia Stiles, and the emotional weight of “The Bourne Legacy” is lost in the elaborate car chase scenes (with the trademark shaky hand-held camera) and tense moments in CIA situation rooms. There simply isn’t much emotion left, most of it already being sorted out in the first two; but the action scenes are certainly distracting, if not compelling, and make up for any lacking emotional depth. The chase scenes and gunfights are the best of the trilogy. Bourne, however, does return to the training facility when he was first inducted into the superagent training program (which includes waterboarding Bourne), which is moving, and eventually finds out his true identity.

Unlike the first two films, however, Greengrass puts his toe, but just his toe, into the pool of heavy ideas. SPOILER ALERT: The final scene, with Bourne in the water after having jumped off a building, is reminiscent of the first scene of the first film. There’s also the question of the CIA essentially having a blank check to carry out extralegal operations, including Operation Treadstone (or Blackbriar, or whatever it became in this film), which Bourne came out of. The shadowy evil boss of the film, who we only see a few times, turns out to be the CIA director, showing that an illegal conspiracy can reach all the way to the top. The message here, of course, is that intelligence operations should come with strong Congressional oversight, and the public would be outraged if it knew some of the CIA’s more insidious activities. There is even a whistleblower at the end.

Damon, Stiles, David Strathairn (Edward Murrow in “Good Night and Good Luck”), Joan Allen and others all turn in pitch-perfect performances. The star remains Damon, however, who’s built an eye-popping critical career, with films such as “Good Will Hunting,” “The Good Shepherd,” “The Departed,” the Ocean’s films and “Syriana.” He’s at his best here, which keeps the film moving along briskly, if not at a breakneck pace. We witness what might be the end of Jason Bourne, and I, for one, am reluctant to return to tuxedoes and casinos.