More for those who believe that the Constitution requires Congress to approve hostilities before the president can wage them. (My earlier post on the subject is here.) Conservatives who take constitutional meaning more seriously should pay more serious attention to the constitutional history before they come to the view that the Declare War Clause requires Congress to approve before President Obama can launch strikes in Syria.
After the constitutional text, the next most important places to look are the other authoritative American legal documents of the Framing period. The Articles of Confederation acted as the existing national constitution at the time of the Constitution’s drafting and ratification, and the state constitutions, which were the next most important constitutional documents that created state governments that were in many ways more powerful than the national government at the time.
The United States in congress assembled, shall have the sole and exclusive right and power of determining on peace and war, except in the cases mentioned in the sixth article . . .
Like Article I, Section 10 of the Constitution, Article IX is revealing because it does not use the phrase “declare war” to mean start or begin military hostilities. If the Framers had wanted to grant Congress all of the power to decide on war, they would have used the same phrase as Article IX: “Congress shall have the sole and exclusive right and power of determining on peace and war.” Article IX uses the words “sole and exclusive,” meaning to me that no other institution has any say in making war. The Constitution of 1787 does not use that language — as it does, for example, with the trial of impeachment by the Senate, which the Supreme Court has indeed read to exclude any other branch from participating.
No State shall engage in any war without the consent of the united States in congress assembled, unless such State be actually invaded by enemies, or shall have received certain advice of a resolution being formed by some nation of Indians to invade such State, and the danger is so imminent as not to admit of a delay till the united States in congress assembled can be consulted; nor shall any State grant commissions to any ships or vessels of war, nor letters of marque or reprisal, except it be after a declaration of war by the united States in congress assembled, and then only against the kingdom or State and the subjects thereof, against which war has been so declared, and under such regulations as shall be established by the united States in congress assembled, unless such State be infested by pirates, in which case vessels of war may be fitted out for that occasion, and kept so long as the danger shall continue, or until the united States in congress assembled shall determine otherwise.
Article VI here shows that declaring war is about changing a legal status between nations, one necessary so that certain other steps, such as issuing a letter of marque and reprisal, could occur. Article VI does not limit states in responding to hostilities with other types of military force until after declaration of war. It has the exact same understanding of the power to declare war that Article X of the Constitution had — declaring war does not mean engaging in war.