system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:When nuclear weapons were added to the US arsenal, why was the ability to launch them given to the President of the United States and not congress?
gpt
Constitutionally, (although not really in practice any more), Congress is the sole authority on declarations of war or authorizations of the use of military force, but the President is the commander in chief of the armed forces. Congress can't tell generals what to do and it can't give or veto military orders. A nuclear attack is a military order and as such only the President has the authority to initiate it.

On a more practical note, if nuclear missiles have already be launched at the US, there would be only a few minutes to authorize a retaliatory strike, and even a functional congress is not capable of acting that quickly. No country in the world with nuclear weapons has that authority given to their legislatures. In every case it's the head of government or the head of state.