Tales of a nation under attack, which recur when public anxiety rises, multiply at theaters and on TV. Steven Spielberg's "War of the Worlds" is acutely attuned to the zeitgeist of post-9/11 America. In this adaptation of the H.G. Wells novel, Earth is still the most desirable piece of real estate in the Milky Way, the envy of the galactic neighborhood. But this retelling of the alien-invasion story, set in modern-day New Jersey rather than Wells' Edwardian London, tacitly acknowledges American fears of an attack on US cities. A principal aspect of the film is the way a nation unites...