In German military history, Bandenbekämpfung (German; "bandit-fighting" or "combating of bandits"; English equivalent of anti-partisan operations), also referred to as Nazi security warfare during World War II, refers to the concept and military doctrine of countering resistance or insurrection in the rear area during wartime through extreme brutality. The doctrine provided a rationale for disregarding the established laws of war and for targeting of any number of groups, from armed guerrillas to the civilian population, as "bandits" or "members of gangs". As applied by the German Empire and later by Nazi Germany, it became instrumental in the mass crimes against humanity committed by the two regimes, including the Herero and Namaqua genocide and the Holocaust. Historian Alex J. Kay estimates that around 1 million civilians may have died as a result of German anti-partisan warfare—excluding actual partisans—among the 13 to 14 million people murdered by the Nazis during World War II. According to historian and television documentary producer, Christopher Hale, there are indications that the term Bandenbekämpfung may go back as far as the Thirty Years' War. Under the German Empire established by Bismarck in 1871 after the Franco-Prussian War—formed as a union of twenty-five German states under the Hohenzollern king of Prussia—Prussian militarism flourished; martial traditions that included the military doctrine of Antoine-Henri Jomini's 1837 treatise, Summary of the Art of War, were put into effect. Some of the theories laid out by Jomini contained instructions for intense offensive operations and the necessity of securing one's "lines of operations". German military officers took this to mean as much attention should be given to logistical operations used to fight the war at the rear as those in the front, and certainly entailed security operations.