“The Hurt Locker,” directed by Kathryn Bigelow from a script by Mark Boal, is the best nondocumentary American feature made yet about the war in Iraq. This may sound like faint praise and also like a commercial death sentence, since movies about that war have not exactly galvanized audiences or risen to the level of art. The squad of well-meaning topical dramas that trudged across the screens in the fall of 2007 were at once hysterical and noncommittal, registering an anxious, high-minded ambivalence that was neither illuminating nor especially entertaining. And the public, perhaps sufficiently enervated and confused by reality, was not eager to see it recreated on screen.