When the state of Israel was established in 1948, it was immediately thrust into war, and rabbis in the religious Zionist community were challenged with constructing a body of Jewish law to deal with this turn of events. Laws had to be "constructed" here because Jewish law had developed mostly during prior centuries when Jews had no state or army, and therefore it contained little material on war. The rabbis in the religious Zionist camp responded to this challenge by creating a substantial corpus of laws on war, and they did so with remarkable ingenuity and creativity. The work of these rabbis represents a fascinating chapter in the history of Jewish law and ethics, but it has attracted relatively little attention from academic scholars. The purpose of the present text is therefore to bring some of their work to light.