Battlestar Galactica (2004)

The benchmark. One battlestar, its commander William Adama and the sole surviving member of the civilian government, Laura Roslin, have to protect the last of humanity while Cylon androids that look human may already be aboard. That split between military command and civilian authority drives the best arguments in the show. Start with the three-hour 2003 miniseries, then the four seasons. The final season divides people, but the first two are as tense as war television gets, and the series won a Peabody Award.