SCXWAP_130214_036
Existing comment: Defining the Conflict: The Prize Cases:

The very definition of the Civil War came before the Court in the Prize Cases (1863), four cases that were combined and argued over twelve days. On the surface, the cases dealt with the legality of the Union's seizure of neutral ships and cargos, or prizes, under a naval blockade of Southern ports. At their core, however, the cases asked the Justices to decide if under the Laws of war this was a conflict between nations or an internal rebellion.

A War between Nations?
Representatives for the ship owners argued that the blockade was illegal unless a recognized state of war existed between belligerent nations. Under the Laws of War, therefore, a blockade could only be legally enforced if the United States of America recognized the Confederate States of America as a belligerent nation. If the conflict was only a rebellion, as the Union claimed, the blockade was illegal and the captured prizes should be released to their original owners.

"A Civil War is never solemnly declared... When the party in rebellion occupy and hold in a hostile manner a portion of territory, have declared their independence, ... have commenced hostilities against their former sovereign, the world acknowledges them as belligerents, and the contest as a war."
-- Justice Robert C. Grier

Or a Civil Rebellion?
The attorneys representing the federal government argued that the conflict was a rebellion, with part of the populace fighting against the sovereignty of the Union. The scope of the conflict, however, was so large that a war existed whether Congress issued a declaration that recognized the Confederacy or not. Under these conditions, the Laws of War did not apply, the blockade was legal, and the capture prizes should be awarded.

Scott's Great Snake, May 1861:
Also known as the Anaconda Plan, this strategy devised by General Winfield Scott called for a naval blockade of Southern ports and sending military troops down the Mississippi River. The image of the snake was commonly associated with the plan, as the blockade would suffocate the Confederacy, like an anaconda.

Laws of War:
A set of international protocols and rules by which nations engage in war. By the mid-19th century, sovereign nations had to be recognized as belligerents, literally "waging war," for certain tactics like a naval blockade to be used legally.

Recognition of No?
In this cartoon, John Bull (representing England) asks Napoleon III (representing France), "Can you recognize that thing they call the C.S.A.?" Napoleon responds, "Well, I think I could, if 'twere not for the Big Fellow who stands in front." The Union did not want the European nations to recognize the Confederacy, fearing they would provide assistance during the war.
Harper's Weekly, September 14, 1861

In a closely contested 5-4 decision, the Court ruled that the blockade was legal and the ships and cargos were awarded in accordance with the prize law. Justice Robert C. Grier's majority opinion stated that the Confederacy was not an independent country but that the Union was engaged in a civil war of such magnitude that it could proceed as if it was at war with another nation. The Court's decision was significant because it broadened the war powers available to the federal government under the Laws of War likely prevented foreign powers from allying with the North.
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