" Levity is good, " notes Arnold Schwarzenegger’s Terminator model T-101. " It relieves tension and the fear of death. " How true. It also makes Terminator 3: Rise of the Machines the best of the film-franchise entries of this dreary summer.

The movie follows the same pattern as the previous two (from 1984 and 1991, one Terminator for each Republican administration) — but then, the time-travel premise does draw on notions of repetition compulsion and the eternal return. The post-apocalyptic machine tyranny of the future sends the latest model Terminator — the lovely T-X (Kristanna Loken), who has the mercurial powers of T2’s failed assassin and also sports a flame-throwing right arm and a smart rust-colored leather suit — to the present day to destroy John Connor (whiny Nick Stahl), the savior-to-be of the human race. The humans of the future, once again, send back as Connor’s protector Schwarzenegger’s dogged cyborg. Connor, Arnold, and not-so-innocent bystander Kate Brewster (Claire Danes) fight and flee and try to prevent the end of the world. Along the way they disclose and discover the twists of fate and, an overlong chase scene or two excepted, the pleasures of trenchant storytelling.

Director Jonathan Mostow, replacing T2’s self-indulgent James Cameron, is an inspired choice: machines features in the lead roles of his Breakdown and U-571, and his flair for mechanics allows him to restore the black humor and subversiveness of the original Terminator. As for Arnold, he’s definitely back, and let’s hope his faith in levity is not as obsolete as T-101’s technology. (109 minutes)