what branch declares war

The branch that declares war according to the U.S. Constitution is Congress. Specifically, Article I, Section 8, Clause 11 of the Constitution grants Congress the sole power to declare war. This means that the legislative branch, not the President or the executive branch, has the authority to formally declare war. The President, however, is empowered to conduct war and repel sudden attacks without prior congressional declaration. Congress has declared war on multiple occasions in U.S. history, including wars against Great Britain, Mexico, Spain, Germany, and others.