It’s a bad sign when a sizable portion of a preview audience starts lurching for the exit before the final fade-out. This thriller involving a plot to assassinate a genocidal African dictator has Nicole Kidman in the title role as a UN interpreter and Sean Penn as a Secret Service agent. I suppose the absence of heat between them could be taken as a sign of the movie’s seriousness, but without a spark to ignite the proceedings even the actors’ craft and Sydney Pollack’s direction don’t count for much. Five people worked on the script; if there was ever any inspiration behind it, there isn’t now. PG-13, 128 min. (JR)