Just to make sure that everyone knows who has the power TO MAKE WAR in the US as opposed to the power TO DECLARE WAR, I will explain the present set up.
The chain of command runs from the president/commander in chief to the Secretary of Defense and from him to the combatant commanders at EUCOM, CENTCOM, Strategic Command, etc. These combatant commands are really just headquarters designed to exercise operational control over forces raised by the service departments; Army, Navy, Air Force and provided to the combatant commands for conduct of operations.
People and institutions NOT in the chain of command; the vice president, the CIA, State Department, Congress, the Joint Chiefs of Staff (an advisory body), the Chairman of the Joint Chiefs of Staff (the head military advisor).
The War Powers Resolution of 1973 gives the president/commander in chief 60 days of unfettered authority to take military action before a justifying report to Congress is required. If the Congress wanted to call a halt to some military action after that its most effective tools would be de-funding the operation or impeachment. What is the chance that either of these things would happen? I don't recall either of those things happening in the past.
With regard to nuclear war, the president/commander in chief has unlimited power to launch an attack, presumably in retaliation,
In fact a combination of political forces that overcomes the president/commander in chief's resistance can take the US to war without congressional action.
Do you really like this set up? pl