I have previously explained in a letter to congressional leaders, signed by myself and other constitutional law scholars, that Congress possesses substantial constitutional authority to regulate ongoing military operations, and even to bring them to an end. I would like to elaborate on those conclusions here and to address more directly the claim that some commentators have been making of late - namely, that once military operations have begun the Constitution essentially prohibits Congress from using its war powers to do anything short of cutting off funding altogether.
In my view, there is simply no support in either the founding materials, the decisions of the Supreme Court, or the actual practices of the executive or legislative branches for a rule that would so dramatically circumscribe Congress's powers in a time of war. Though congressional war powers are not plenary, neither do they limit the legislature solely to reliance upon a complete termination of funding in regulating the scope, duration or size of a military operation. To the contrary, our constitutional tradition shows that measures such as those now being considered concerning military operations in Iraq - whether they place caps on troop levels, restrictions on the introduction of new troops, or establish a date certain by which troops must be redeployed - are clearly constitutional exercises of well-established congressional war powers.
The clearest sources of congressional authority to regulate ongoing military operations are to be found in the spending powers the Constitution gives to the legislative branch. A military operation necessarily requires the expenditure of considerable funds. The Congress is alone vested with the constitutional power to appropriate money from the Treasury, and it is given specific spending powers with respect to the Army and Navy. It bears emphasis, however, that legislative war powers are not solely a function of Congress' s power of the purse. The Constitution names the President as the Commander in Chief, but it also expressly confers upon Congress an impressive array of war powers that are not tied to its general appropriations power (for example, the power "to make rules for the government and regulation of the land and naval forces.").
Some have argued that Congress's power over appropriations... is severely constrained when military hostilities are actually underway. They have suggested that the outbreak of hostilities cuts short, in effect, the broad authority that the Congress otherwise enjoys over the use of military force.
This argument is usually framed in terms of a constitutional concern about congressional micromanagement of military operations in the field. Against this suggestion, however, is the fact that the Supreme Court has often described the scope of Congress's powers over the conduct of war in quite broad terms. The Court, during World War II, made clear that the two branches' shared power in this regard "extends to every matter and activity so related to war as substantially to affect its conduct and progress." That power "is not restricted to the winning of victories in the field and the repulse of enemy forces. It embraces every phase of the national defense, including the protection of war materials and the members of the armed forces from injury and from the dangers which attend the rise, prosecution and progress of war.”
The constitutional text reflects, after all, a vital competing concern that must be kept in mind - namely, a concern about the absence of adequate legislative checks on executive action in wartime. And while there is no direct support for the view that the Congress is powerless to limit the conduct of war by statute, there is abundant evidence revealing the Framers' concerns about such unchecked presidential authority. The founding generation obviously did not intend to recreate a chief executive who would in effect be beyond control, especially in military affairs.
In consequence, between the extreme poles of outright abdication and what might be thought to be undue micromanagement, there necessarily lies a substantial zone within which the Congress retains authority over the conduct of war. In my judgment, proposals to set flat caps on troop levels, limit the introduction of additional forces into the theater of operations, or to bring the deployment itself to an end through curtailment of funds fall well within that permissible zone of authority.
Such measures would not undermine the one specific wartime power that the Constitution does clearly assign to the President - that he and no other executive officer be the chief superintendent of the armed forces. The measures now being considered do not in any respect interfere with the constitutionally established internal chain of military command. They do not attempt to countermand the President's judgment as to who within the military may command the forces in the field. Nor do they regulate the President's power of superintendence over the armed forces that have been made available to him by interfering with the way information may flow up or down the line. They simply define the amount of resources that the President will have under his unified and unchallenged command. For that reason, they cannot be said to be inconsistent with the Constitution's designation of the President as being the chief officer within the military hierarchy.
In addition, such measures clearly do not amount to legislative attempts to usurp anything like the day-to-day operational control over the minutiae of ongoing military that some have pointed to in attempting to give substance to the concern about micromanagement.
In sum, the measures now under consideration all afford the President broad latitude over tactical questions concerning those forces that are authorized to be in the field, for so long as that authorization lasts. But that, of course, is the full extent of the power that one Congress may ever confer on the President when it authorizes him to use military force, unless one accepts the dangerous doctrine that a President who has been given the power to go to war by one legislature becomes at that moment essentially free of subsequent legislative constraint altogether. As a result, whether or not Congress could enact even more restrictive measures, as it is has on occasion done, measures of the type now being considered clearly fall within Congress's war powers just as did the statute initially authorizing the use of military force in Iraq (and not any place the President should choose), even though it, too, identified certain bounds within which the President's authority was to be exercised.
A conclusion that the Commander in Chief enjoys an illimitable power to escalate or augment a military campaign that was authorized years earlier, and presumably thus to retain the power in connection with it to use, as he sees fit, any of the million persons that may be enlisted in the armed forces at a given time, is simply not consistent with the principles that animated the delineation of war powers set forth in the Constitution's text. The Framers were too concerned about unchecked executive power, especially in times of war, to countenance such a notion. Not surprisingly, therefore, such a conclusion is not supported by either the rulings of the Supreme Court or the more than two centuries of actual practice of the political branches themselves. In consequence, there is no basis for adjudging a restriction on troop increases, a cap on troop levels, or the establishment of a date certain for troop redeployment as being anything other than legitimate and constitutional.
The complete text of Barron's opening statement is available here.