Gregory Nava’s 1997 biopic about the Mexican-American pop star Selena Quintanilla Perez, killed at the age of 23 by the president of her fan club, is typical of the genre’s excesses, but I enjoyed quite a bit of it, in large part because of the energy and charisma of Jennifer Lopez in the title role. The film adeptly points to the contradiction inherent in being Mexican-American—too Mexican for white Americans but too American for Mexicans, as Selena’s cantankerous father and manager (Edward James Olmos) explains. The handling of the musical numbers through split-screen and crosscutting techniques is also effective. What doesn’t work at all is the treatment of Selena’s murder and the events that lead to it. Even if one discounts the rumor that her death grew out of a lovers’ quarrel—which, if true, would make nonsense of much of this movie’s touching love story—the motivation offered here is cursory and unconvincing. With Jon Seda, Jacob Vargas, Lupe Ontiveros, and Jackie Guerra. 127 min.