Limit of President's authority as CINC?

Factual Questions
1

The Constitution says only Congress can declare war and that the President is the Commander in Chief of the armed forces. So where exactly does one authority end and another begin?

Congress hasn’t declared war since WWII, but we’ve had plenty to fight about since then–Korea, Vietnam, Desert Storm just to name a few. LBJ had the Gulf of Tonkin resolution, Congress approved the 1991 invasion, and Congress is now debating what to do with Iraq again.

Suppose Congress votes against a resolution to invade Iraq. Could the president go ahead with military action anyway as CINC?

2

IIRC, the President can send troops out for up to 90 days, after which time he’ll need the approval of Congress for extended action or withdraw the troops. Thing is, in 90 days you can really start some shit with the US military at your disposal. Congress might be forced to approve just to get our boys and girls home safely.

3

This is a result of the War Powers Act, but if I remember correctly, there is some question as to whether this statute is constitutional.

4

This has been debated since the beginning of the Republic, but the practical reality is that, in the short run at least, the president’s powers as Commander-in-Chief are virtually unlimited.

Could he? Yes. Would it be politically wise to do so? No.

One way to think about this is, who would stop the president? He gives the order to start dropping bombs. Can you imagine a court granting an injunction telling a general to disobey an order from the president? One thinks not.

In the long run, of course, Congress can fight back. They can cut off funds for particular millitary programs, pass explicit resolutions stating their opposition to military action, and if the president persists, use the ultimate remedy of impeachment.

Congress did pass the War Powers Resolution in 1973, laying out guidelines for how the president and Congress should interact when military action short of a declaration of war is required. Sometimes presidents follow the guidelines, and sometimes they don’t. Nothing in the WPR changes the practical reality outlined above.