Congress' Power to Authorize Limited Hostilities
Does Congress have constitutional power to authorize limited strikes on Syria? In his otherwise outstanding post on Congress' war powers, Michael Stokes Paulsen suggests that the answer might be no:
... [I]t is fruitless, and equally unconstitutional, for Congress to authorize the use of force but attempt to micro-manage how it is to be used (as some versions of the proposed resolution now being debated would do). As noted, the conduct of war, once authorized, lies in the hands of the president. Congress has the power to declare war, and the president does not. But the president has the power to conduct war as Commander in Chief—and Congress does not.
I'm not sure which versions of the resolution are meant here, but the principal proposal -- (a) limiting the use of force to degrading Syria's chemical weapons capacity, and (b) limiting the use of force to air power -- seems well within Congress' power to declare a limited war.
The leading article on this subject is by Saikrishna Prakash in the Texas Law Review: The Separation and Overlap of Military Powers. From the abstract:
Absent from war-powers scholarship is an account of when war and military powers separate and when they overlap. Making arguments sounding in text, structure, and history, this Article supplies such a theory. Numerous English statutes and practices help identify the meaning of the Constitution’s war and military powers. Additional insights come from the Revolutionary War and the half-dozen or so wars fought in the three decades after 1789. In those early years, Congress micromanaged military and wartime operations. Presidents (and their advisors) acquiesced to these congressional assertions of power, expressing rather narrow understandings of presidential power over war and military matters. Using early history as a guide, this Article argues that the Constitution grants Congress complete control over all war and military matters. Some authorities, such as the powers to declare war and establish a system of military justice, rest exclusively with Congress. Military authorities not granted exclusively to Congress vest concurrently with the President and Congress, meaning that either can exercise such powers. In this area of overlap, where congressional statutes conflict with executive orders, the former always trump the latter. Tempering Congress’s ability to micromanage military operations are significant institutional and constitutional constraints that typically make it impossible for Congress to move military assets on a far-off battlefield. In sum, the Constitution creates a powerful Commander in Chief who may direct military operations in a host of ways but who nonetheless lacks any exclusive military powers and is thus subject to congressional direction in all war and military matters.
While I would not go quite as far as Professor Prakash (see here), I agree that Congress has substantial ability to set the goals and limits of the use of force in connection with an authorization of war. To take a leading example from post-ratification practice, the limited war with France in 1798 shows general acceptance of Congress' ability to authorize limited uses of force. In response to French attacks on U.S. shipping, Congress initially authorized the President only to use naval force against French warships that had actually attacked U.S. shipping or were "hovering" along the coasts for that purpose. (Act of May 28, 1798). Later, Congress broadened the authorization to allow attacks on French warships anywhere in U.S. waters or on the high seas. (Act of July 9, 1798). But Congress' authorizations did not extend to, for example, attacking land installations in the French Caribbean. And in each case the authorizations only allowed the President to "instruct the commanders of public armed vessels" of the United States to use force against the French. Thus Congress, faced with French provocations that would have justified resort to full scale resort to war, authorized only a limited response -- limited both as to what type of force could be used (naval) and where that force could be applied (in U.S. waters or the high seas).
Addressing this situation in Bas v. Tingy (1800) the Supreme Court found a state of limited war to exist under Congress' statutes, and did not see any constitutional problem with it. Justice Chase wrote:
Congress is empowered to declare a general war, or Congress may wage a limited war, limited in place, in objects, and in time. If a general war is declared, its extent and operations are only restricted and regulated by the jus belli, forming a part of the law of nations, but if a partial war is waged, its extent and operation depend on our municipal laws.
What, then, is the nature of the contest subsisting between American and France? In my judgment it is a limited partial war. Congress has not declared war in general terms, but Congress has authorized hostilities on the high seas by certain persons in certain cases. There is no authority given to commit hostilities on land, to capture unarmed French vessels, nor even to capture French armed vessels lying in a French port, ... So far it is unquestionably a partial war; but nevertheless it is a public war, on account of the public authority from which it emanates.
And as Justice Washington added, limited war was a common feature of eighteenth-century international law and practice:
But hostilities may subsist between two nations more confined in its nature and extent, being limited as to places, persons, and things, and this is more properly termed imperfect war; because not solemn, and because those who are authorized to commit hostilities, act under special authority, and can go no further than to the extent of their commission. Still, however, it is public war, because it is an external contention by force between some of the members of the two nations, authorized by the legitimate powers. It is a war between the two nations, though all the members are not authorized to commit hostilities such as in a solemn war, where the government restrain the general power.
None of the Justices suggested any doubt that Congress had acted properly in authorizing a limited war (nor was the point controversial either in Congress or in the executive branch).
As in other situations, the post-ratification practice is not conclusive of the Constitution's original meaning, but it is good evidence, especially when the text and other contextual factors do not point strongly in the other direction.