More on the federal separation of war powers
In an earlier post, I made the point that the Constitution empowers the Congress, not the president, to make war as well as declare war. (The context was whether the USA is actually at war because no Congressional declaration of war had been made.) Eugene Volokh (link at left) has written about this topic a lot, and he read what I wrote and kindly corrected me that the Constitution does not specifically empower the Congress to make war, at least not in such terms.

I somewhat sheepishly responded by email thus:

. . . I'll relate my historical understanding. The conduct of war (its command and direction) is the province of the executive, but Congress' enumerated powers in Art. I, Sec. 8, gives the Congress very substantial authority in military matters, especially the power of the purse over the defense establishment and the power to specify the size of the armed forces.

Again, merely recollecting readings from times past (maybe way past!) the understanding of the Framers was that the presidency would not be nearly the powerful office it became not too many years after Washington's terms. They certainly did not wish to invest the American president with the sort of powers of the English monarch to make war on his own. They thought that the president would direct the army and navy in war only after the Congress, representing the people's will, gave him the authority. For example, Federalist 44 indicates that without consent of Congress no state could "engage in war unless actually invaded, or in such imminent danger as will not admit of delay," clearly indicating (I think) the principle that making war except in true emergency was reserved to the Congress.

Hamilton wrote in Federalist 69, The Real Character of the Executive,

"The President is to be commander-in-chief of the army and navy of the United States. In this respect his authority would be nominally the same with that of the king of Great Britain, but in substance much inferior to it [emphasis added]. It would amount to nothing more than the supreme command and direction of the military and naval forces, as first General and admiral of the Confederacy; while that of the British king extends to the DECLARING of war and to the RAISING and REGULATING of fleets and armies, all which, by the Constitution under consideration, would appertain to the legislature."

So I think I am standing of fairly solid ground in saying that making war as well as declaring it is a prerogative of the Congress, but I freely admit that your expertise is certainly superior to mine. I'd be interested in your other thoughts!

I believe that the Framers did not intend for the presidency to have the authority under the Constitution to embark on military action without prior approval of the Congress, except in emegency. But neither does the Constitution actually require the Congress to "declare" war in order for the president to conduct such operations. The Congress may authorize military action by the executive in whatever way it pleases.

Professor Volokh wrote back, "I agree with you that Congress was supposed to play an important role in controlling warmaking via the power of the purse, though the President was in charge of the other decisions." And I urge you to read this posting on his site, which seems to me to be the last word on the topic in light of the present war. He quotes Senator Joe Biden as saying,

Under the Constitution, there is simply no distinction ... Louis Fisher(?) and others can tell you, there is no distinction between a formal declaration of war, and an authorization of use of force. There is none for Constitutional purposes. None whatsoever. And we defined in that Use of Force Act that we passed, what ... against whom we were moving, and what authority was granted to the President.

So yes, the US is genuinely at war, and yes, the separation of powers of the Constitution has been maintained.