The reporter Marie Colvin was killed in Homs in February 2012. A Private War, Matthew Heineman’s movie based on her life, begins with archival footage of Colvin being asked by an interviewer what she would want a young journalist to know about being a war correspondent. Her answer comes in two parts: first, that you should care enough to write in a way that makes others care; second, some tough-sounding advice on not acknowledging fear until the job is done.