This absorbing adaptation of a typically intricate Tom Clancy novel takes a couple of big gambles. The first is replacing Harrison Ford as CIA analyst Jack Ryan with Ben Affleck, who's 30 years younger - the story has been re-written to accommodate a less savvy, lower-ranking hero. The other is a shocking act of international terrorism that takes place around the halfway mark and transforms the film from a thinking person's thriller into a contemporary version of Sidney Lumet's doom-laden Fail-Safe. Unexpectedly, perhaps, the appealing Affleck and director Phil Alden Robinson (Field of Dreams, Sneakers) pull it off, with the help of a superior supporting cast that includes Morgan Freeman and James Cromwell, as well as the disturbing post-11 September credibility of the terrorist scenario. Only Alan Bates rings a false note as the one-dimensional villain, but the intelligent twists and taut pacing ensure entertaining, albeit occasionally uncomfortable, viewing.

When the president of Russia suddenly dies, a man whose politics are virtually unknown succeeds him. The change in political leaders sparks paranoia among American CIA officials, so CIA director Bill Cabot recruits a young analyst to supply insight and advice on the situation. Then the unthinkable happens: a nuclear bomb explodes in a U.S. city, and America is quick to blame the Russians.