Without in any way meaning to detract from your arguments respecting Congress' power to prohibit funds from being used to increase the number of troops in Iraq, it seems to me that Article I Section 8 clauses 14 and 16 authorize Congress to pass a law requiring the Secretary of Defense and the chiefs of the military branches to order back to their U.S. bases a sufficient number of troops to bring troop levels down, by a specified dates, to whatever levels Congress chooses should the President not take those steps. The broad authority there granted to Congress to make rules for the government and regulation of the armed forces was intended to prevent the armed forces from becoming an instrument solely of the Executive Branch.
Dear Professor Goldman:
Being rather ignorant in the premises, I do not know whether clauses 14 and 16 provide the power you suggest. I defer to your interpretation of their purpose.
I do think, however, that Congress has the power under Clauses 8 and 18 (the declaration of war and necessary and proper clauses) to enact your suggested type of law ordering troop levels in Iraq down to numbers established by Congress (including the number zero) by dates specified by the legislature. As said in my post, it has been well established, at least since the Bas and Talbot cases in 1800 and 1801, that Congress sets the parameters of a war effort - - that it can establish what uses of force shall or shall not be permissible, that it can determine how big or small a war shall be fought. Your suggested type of law would be an exercise of this undoubted congressional power to set the limits on war. It would also, I note, avoid the false fear that a cut off of funds would jeopardize our troops (which a cut off would not do, of course, if it contained an exception, as it should, for the use of funds needed to protect the troops during withdrawal).
To further show that Clause 8 would sustain your suggested law, one need only ask whether Congress has the constitutional power to end the war by voting to repeal its authorization of war, and to override a veto of the repealer: Of course Congress has the constitutional authority to do these things. There can be no legitimate argument on this score. As I see it, your suggested type of law is merely an alternative way of carrying out the congressional power to terminate a war.
Let me thank you, then, for a most excellent suggestion on what Congress might do. Congress should pay close attention to the possibilities of enacting the type of law you have suggested, if it does not actually cut off funds for the war.
All the best.
Lawrence R. Velvel