Wars have existed since ancient times, and people use violence to achieve their goals for wealth and interests. With the development of human society, the means of war are constantly changing. /kloc-The industrial revolution since the middle of the 0/9th century has made the real armor of war in the industrial age rumble in the 20th century with great destructive power, leaving behind Verdun's "meat grinder", thousands of "machine" wars over Britain and thousands of "car" wars on the battlefield in Kursk, tens of millions of dead people in two world wars and the ruins of Hiroshima and Nagasaki. In the second half of the 20th century, the form of war began to change, and wars in the information age began to take shape. Therefore, there is an elective content "War and Peace in the 20th Century" in middle school history textbooks. With the deepening of the exam, we have to evaluate it correctly.

* The purpose of the war: from "attacking the city and plundering the land" to economic interests; From unconstrained to restricted; From militarization of political purpose to economization of military and political purpose. "Destroying the enemy", specifically "physically destroying the enemy", was the direct goal pursued by the war in the first half of the 20th century. The wars in the 20th century were wars in which imperialism plundered colonies crazily, including the war of independence launched by colonial countries later. An obvious feature of these wars is the struggle for living space to "attack the city and plunder the land". The military task is to destroy all the military forces that confront it, even at the expense of mass killing. However, at the heavy cost of two world wars, mankind ruthlessly declared the end of this "absolute" war of unrestrained pursuit of national goals.

After the end of World War II, the form of war changed. The absolute war goal of "attacking the city and plundering the land" is difficult to achieve militarily, but it will also be passive politically, and the economic loss will outweigh the gain. The purpose of the war gradually changed from lack of restraint to limitation, and turned to gain certain political and economic control. The war no longer revolves around plundering the colonies, and the standard of victory is no longer based on the area of "attacking the city and plundering the land".

After the emergence of nuclear weapons and information weapons, war has the means to directly achieve strategic goals and the ability to flexibly control these means. The purpose of war is very flexible, and it is not easy to lead to absoluteness or rigidity in fierce confrontation. War is closer to politics, and politics has the means to achieve its own goals directly. War in the modern sense may not be completely manifested in the battlefield, nor may it go through the process of changing the balance of power, but it may become a kind of "will" confrontation war with increased political color, showing some kind of "indirect" and "potential" military contest. In this case, the military purpose pursued by the war is closer to the political purpose, and it is strictly controlled by politics, showing the characteristics of "finiteness".

An obvious sign of the change in the purpose of modern warfare is to highlight "economic interests." Directly destroying or affecting comprehensive national strength, especially economic strength, has become an ideal choice for war decision makers to achieve war goals more effectively. Economic factors play a prominent role in the war, which is not only the cause of the war, but also the main target of the attack.

:: The subject of war: from the state to the alliance, until individuals wage war; There are even "war companies" in America.

At the beginning of the 20th century, the main body of war was the country. With the emergence of a large number of international organizations and transnational groups, the dominant position of the state in international exchanges has been challenged, and the subject of war marked by the state has changed accordingly.