Tolstoy had a very critical view of war in War and Peace. Some of the main points he conveys about war through the novel include:
• The horror and futility of war. War causes immense suffering, death and destruction for little gain. This is shown through many of the characters who go through terrible experiences in the wars.
• The unpredictability and chaos of war. War is dominated by confusion, misinformation, unintended consequences and random chance. Grand plans rarely survive contact with the enemy. This highlights how military leaders and governments cannot control war.
• The insignificance of individual free will. While characters make choices that lead them to war, they are ultimately trapped by the bigger forces of history and cannot escape their fate. So individuals are powerless against the sweep of events.
• The way young men are sacrificed for the ambitions of leaders. Much of the burden of war falls on the common soldiers, who are often forced to fight and die for causes they don't fully understand.
• How war hardens and coarsens people. Exposure to violence and death desensitizes people and strips away humanity. Many characters are profoundly changed by their experiences in the war.
• The lies and propaganda that are used to justify war. Governments and military leaders continually spread misleading or false information to rally support for the war effort. The truth is often obscured by propaganda.
So in many ways, Tolstoy saw war as a terrifying, futile and brutalizing force that is beyond any individual's control and is rarely justified. That is the overarching point he seems to convey about war in the novel.