According to the us constitution, which branch of government has to declare war?

Commander in Chief of the Army and Navy of the United States, and of the Militia of the several States, when called into the actual Service of the United States

Explanation:

The president can declare war because he is the leader of the nation. He has full contact with any of the other nations leaders. If he feels like he needs war, then he needs war.

checks and balances are needed to keep the government running smoothly, they allow the three branches of government to overrule one another so that one branch of government does not become too powerful.

the images of war are haunting