What branch of state government declare war?

In the United States, the power to declare war is primarily vested in Congress, which is the legislative branch of the federal government. The Constitution grants Congress the authority to declare war, while the President, as the Commander-in-Chief of the armed forces, has the power to direct military operations. However, the President cannot officially declare war without Congressional approval. This division of powers is designed to ensure a system of checks and balances between the branches of government.