Answer: Breakthrough progress has been made in the reform of the leadership and management system and the joint combat command system, important results have been achieved in the reform of optimizing the scale and structure, improving policy systems, and promoting the in-depth development of military-civilian integration, and strive to build a capable A modern military force system with Chinese characteristics that wins informationized wars and effectively performs missions and tasks, and further improves the socialist military system with Chinese characteristics.

1. National defense comes with the emergence of a country and serves national interests. Churchill has a famous saying: "We have no eternal friends or eternal enemies, only eternal interests." The national defense in this sentence is directly related to national security, national dignity, and social development.

2. Modern national defense is also called social national defense, major national defense, and all-people national defense, including armed construction, national defense system, military science and technology and industry, national defense engineering, military transportation and communications, manpower mobilization, national defense education, and national defense regulations. It is a large and complex system. From the supreme head of state to every citizen, from military to politics, economy, culture, education, science and technology and ideology, they are all closely related to it.

3. Modern national defense takes military power as its core, and also includes related non-military forces; it attaches great importance to the country’s war potential, especially its wartime mobilization efficiency; it is also a comprehensive system focusing on economy and science and technology. Competition for national power. The modern army is a knowledge- and technology-intensive armed group that emphasizes quality army building over "human sea tactics." The role of national defense in peacetime is to deter, requiring victory without fighting; in wartime, the responsibility of national defense is to conduct actual combat, and the goal is victory.