Why did the United States launch the Vietnam War?

The United States launched the Vietnam War:

First: use force to deal with socialist countries and regimes to prevent the endless expansion of the socialist camp. The national liberation movement led by Ho Chi Minh obviously With this tendency, it is not conducive to the global strategic interests of the United States.

Second: The global strategic competition between the United States and the Soviet Union.

Third: This is a specific step for the United States to implement its global strategic goals. The United States has demonstrated a strong desire for hegemony in military strikes.

Fourth: If Vietnam is occupied by the United States, it can deter the Soviet Union and China strategically.