Phase 1: Crusaders enter the Holy City, Jerusalem Phase 2: Napoleon's campaign of 1806, culminating in the battle of Jena - the decisive importance of artillery Phase 3: During the Cold War American families prepared for a nuclear attack - psychological pressure

• In the first phase, human value – honor, courage, intelligence, ability, and physical strength – was the main factor of waging war. This phase began with the war between the first sons of Adam, and extended to the wars of the late Medieval Ages. The prototype of this phase is the war waged by the Crusades.

• In the second phase, the introduction of gun powder made a major change in the way war was waged. The element of human value was still present, but the material capacity of having cannons and bombs emerged as a decisive element in war. This phase went from the late Medieval Ages until the last days of World War II. The prototype of this phase is the war waged by Napoleon.

• In the third phase, with the chastisement of Hiroshima and Nagasaki, the atomic bomb was introduced in war. With this, the factor of human value almost completely lost its role: supremacy of honor, courage, intelligence, or the prowess of one side over another became secondary matters. What really counted was whether one had the bomb. This weapon did not permit selection to be made between military and civilian targets, as happened in the previous phases. It caused an indiscriminate destruction both during its explosion and after it, with the radioactivity that spread unrestrained over enormous areas. Militarily speaking, this phase actually existed only in the bombardment of Hiroshima and Nagasaki. After this, the atomic weapon was no longer used.

Psychologically, however, its effect was more far-reaching because of its potential danger. To achieve a military supremacy, the nuclear arms race began between two super-powers, the US and the USSR. This race characterized the Cold War. Many other countries also had access to nuclear weapons even though they did not enter the nuclear race. By a kind of agreement of good sense more than any international treatise, nuclear weapons have not been used in war.

• Presently we are witnessing the naissance of a fourth phase in the history of war with the two Gulf Wars against Iraq in 1991 and 2003. The technological and electronic advancements that direct the bomb-carrying missiles have permitted a tight precision in hitting targets and accurately controlling their power of destruction. This has made war a phenomenon much less dangerous than most of the wars in the second phase and, of course, an operation incomparably less dangerous than the atomic war.