At the very beginnings of the Civil War, Abraham Lincoln did not ask Congress to declare war, as that would legitimize the Confederacy as a foreign nation, as if they had seceded already. Instead, President Lincoln set up a naval blockade. During the blockade, the Union Navy seized a number of ships headed for the southern ports to sell goods. If there had been a formal war, the seizure of ships would be fair, however, the Congress had not declared war against the Confederacy. The Prize cases were named after an admiralty rule about capturing ships: if one navy capture a ship from an enemy’s fleet during a war, the ship could be kept as a “prize”. In the Union’s eyes, the ships captured in southern waters were prizes, however that was questioned due to the lack of a formal declaration of war. Although this case dealt specifically with the seized ships, it seeped further into the issue of how Presidents can respond to warlike behavior against the Union without prior Congressional approval, especially if there is no formal war. To decide the case, the court looked to precedent set in Great Britain about international law related to a similar matter. British interpretation would label the Confederacy as a provocateur of war, but was not itself a nation, so formal war could not be declared. The Supreme Court agreed that the President’s actions were legal because a civil war had existed de facto since April 12, 1861 with the battle at Fort Sumter. Justice Grier, who wrote the opinion, also noted that it’s the President’s job to protect the Union and the Constitution. If a situation is immediate, the President must respond as Commander-in-Chief rather than wait for Congress to agree.

Brig Amy Warwick

67 U.S. 635 (1863)

(Prize Cases; Authority of the President to Repel Attacks on the Union)


These were cases in which the vessels named, together with their cargoes, were severally captured and brought in as prizes by public ships of the United States.

The Amy Warwick was a merchant vessel and belonged to Richmond. Her registered owners were David and William Currie, Abraham Warwick and George W. Allen, who resided at that place. Previous to her capture she had made a voyage from New York to Richmond, and thence to Rio de Janeiro, Brazil. At the last-named port, she shipped a cargo of coffee 5,100 bags, to be delivered at New York, Philadelphia, Baltimore or Richmond, according to the orders which the master would receive at Hampton Roads. She was on her voyage from Rio to Hampton Roads and off Cape Henry when she was captured (July 10th, 1861) by the Quaker City. At the time of the capture, the barque was sailing under American colors, and her commander was ignorant of the war. The Quaker City carried her into Boston, where she was libeled as enemy's property. The claimants of the vessel were the persons already named as owners. James Dunlap, Robert Edmonds, John L. Phipps, and Charles Brown claimed the cargo. The claimants in their several answers denied any hostility on their part to the Government or Laws of the United States, averred that the master was ignorant of any blockade, embargo or other interdiction of commerce with the ports of Virginia, and asserted generally that the capture was unlawful.

The Crenshaw was captured by the United States Steamer Star, at the mouth of James River, on the 17th of May, 1861. She was bound for Liverpool with a cargo of tobacco from Richmond and was owned by David and William Currie, who admitted the existence of an insurrection in Virginia against the Laws and Government of the United States but averred that they were innocent of it. The claimants of the cargo made similar answers, and all the claimants assured that they had no such notice of the blockade as rendered the vessel or cargo liable to seizure for leaving the port of Richmond at the time when the voyage was commenced. She was condemned as prize on the ground that she had broken, or was attempting to break, the blockade at the time of her capture.

The Hiawatha was a British barque and was on her voyage from Richmond to Liverpool with a cargo of tobacco. She left Richmond on the 17th of May, 1861 and was captured in Hamption Roads on the 20th by the Minnesota and taken to New York. Her owners were Miller, Massman & Co., of Liverpool, who denied her liability to capture and condemnation on the ground that no sufficient notice had been given of the blockade. The claimants of the cargo put their right to restoration upon a similar basis.

The Brilliante was a Mexican schooner, owned by Rafael Preciat and Julian Gual, residents of Campeche. She had on board a cargo of flour, part of which was owned by the owners of the vessel, and part the Senores Ybana & Donde, who were also Mexican citizens. She had a regular clearance at Campeche for New Orleans and had made the voyage between those ports. At New Orleans she took in her cargo of flour, part to be delivered at Sisal and part at Campeche and took a clearance for both those places. On her homeward voyage she anchored in Biloxi Bay, intending to communicate with some vessel of the blockading fleet and get a permit to go to sea, and while so at anchor she was taken by two boats sent off from the Massachusetts. She was carried into Key West, where the legal proceedings against her were prosecuted in the District Court of the United States for the District of Florida.

That a blockade de facto actually existed and was formally declared and notified by the President on the 27th and 30th of April, 1861, is an admitted fact in these cases.

Brig Amy Warwick, 67 U.S. 635 (1863)

Brig Amy Warwick, 67 U.S. 635 (1863)

Brig Amy Warwick, 67 U.S. 635 (1863)

Brig Amy Warwick, 67 U.S. 635 (1863)


1st. Had the President a right to institute a blockade of ports in possession of persons in armed rebellion against the Government, on the principles of international law, as known and acknowledged among civilized States?

2d. Was the property of persons domiciled or residing within those States a proper subject of capture on the sea as "enemies' property?" Is the property of all persons residing within the territory of the States now in rebellion, captured on the high seas, to be treated as "enemies' property" whether the owner be in arms against the Government or not?

Whether, at the time this blockade was instituted, a state of war existed which would justify a resort to these means of subduing the hostile force.


That the President, as the Executive Chief of the Government and Commander-in-chief of the Army and Navy, was the proper person to make such notification, has not been, and cannot be disputed.

The right of prize and capture has its origin in the "jus belli," and is governed and adjudged under the law of nations. To legitimate the capture of a neutral vessel or property on the high seas, a war must exist de facto, and the neutral must have a knowledge or notice of the intention of one of the parties belligerent to use this mode of coercion against a port, city, or territory, in possession of the other.

War has been well defined to be, "That state in which a nation prosecutes its right by force."

The parties belligerent in a public war are independent nations. But it is not necessary to constitute war, that both parties should be acknowledged as independent nations or sovereign States. A war may exist where one of the belligerents, claims sovereign rights as against the other.

Insurrection against a government may or may not culminate in an organized rebellion, but a civil war always begins by insurrection against the lawful authority of the Government. A civil war is never solemnly declared; it becomes such by its accidents -- the number, power, and organization of the persons who originate and carry it on. When the party in rebellion occupy and hold in a hostile manner a certain portion of territory; have declared their independence; have cast off their allegiance; have organized armies; have commenced hostilities against their former sovereign, the world acknowledges them as belligerents, and the contest a war. They claim to be in arms to establish their liberty and independence, in order to become a sovereign State, while the sovereign party treats them as insurgents and rebels who owe allegiance, and who should be punished with death for their treason.

The true test of its existence, as found in the writing of the sages of the common law, may be thus summarily stated: "When the regular course of justice is interrupted by revolt, rebellion, or insurrection, so that the Courts of Justice cannot be kept open, civil war exists and hostilities may be prosecuted on the same footing as if those opposing the Government were foreign enemies invading the land."

By the Constitution, Congress alone has the power to declare a national or foreign war. It cannot declare was against a State, or any number of States, by virtue of any clause in the Constitution. The Constitution confers on the President the whole Executive power. He is bound to take care that the laws be faithfully executed. He is Commander-in-chief of the Army and Navy of the United States, and of the militia of the several States when called into the actual service of the United States. He has no power to initiate or declare a war either against a foreign nation or a domestic State. But by the Acts of Congress of February 28th, 1795, and 3d of March, 1807, he is authorized to called out the militia and use the military and naval forces of the United States in case of invasion by foreign nations, and to suppress insurrection against the government of a State or of the United States.

If a war be made by invasion of a foreign nation, the President is not only authorized but bound to resist force by force. He does not initiate the war but is bound to accept the challenge without waiting for any special legislative authority. And whether the hostile party be a foreign invader or States organized in rebellion, it is none the less a war, although the declaration of it be "unilateral."

If it were necessary to the technical existence of a war, that it should have a legislative sanction, we find it in almost every act passed at the extraordinary session of the Legislature of 1861, which was wholly employed in enacting laws to enable the Government to prosecute the war with vigor and efficiency. And finally, in 1861, we find Congress "ex major cautela" and in anticipation of such astute objections, passing an act "approving, legalizing, and making valid all the acts, proclamations, and orders of the President, &c., as if they had been issued and done under the previous express authority and direction of the Congress of the United States."

Under the very peculiar Constitution of this Government, although the citizens owe supreme allegiance to the Federal Government, they owe also a qualified allegiance to the State in which they are domiciled. Their persons and property are subject to its laws.

Hence, in organizing this rebellion, they have acted as States claiming to be sovereign over all persons and property within their respective limits and asserting a right to absolve their citizens from their allegiance to the Federal Government. Several of these States have combined to form a new confederacy, claiming to be acknowledged by the world as a sovereign State. Their right to do so is now being decided by wager of battle. The ports and territory of each of these States are held in hostility to the General Government. It is no loose, unorganized insurrection, having no defined boundary or possession. It has a boundary marked by lines of bayonets, and which can be crossed only by force -- south of this line is enemies' territory because it is claimed and held in possession by an organized, hostile and belligerent power.

All persons residing within this territory whose property may be used to increase the revenues of the hostile power are, in this contest, liable to be treated as enemies, though not foreigners. They have cast off their allegiance and made war on their Government and are none the less enemies because they are traitors.


Question 1:

Whether the President in fulfilling his duties, as Commander in-chief, in suppressing an insurrection, has met with such armed hostile resistance, and a civil war of such alarming proportions as will compel him to accord to them the character of belligerents, is a question to be decided by him, and this Court must be governed by the decisions and acts of the political department of the Government to which this power was entrusted. "He must determine what degree of force the crisis demands." The proclamation of blockade is itself official and conclusive evidence to the Court that a state of war existed which demanded and authorized a recourse to such a measure, under the circumstances peculiar to the case.

On this first question, we are of the opinion that the President had a right, jure belli, to institute a blockade of ports in possession of the States in rebellion, which neutrals are bound to regard.

Question 2:

The produce of the soil of the hostile territory, as well as other property engaged in the commerce of the hostile power, as the source of its wealth and strength, are always regarded as legitimate prize, without regard to the domicile of the owner, and much more so if he reside and trade within their territory.

Is there anything we left out? Anything we should remove? Let us know your thoughts!


Key Takeaway

Only Congress can declare war, but when the facts suggest a war is already ongoing or there is an insurrection, the president can derive his power from his position as commander of the army and navy to respond to events.

Court Syllabus:

1 Neutrals may question the existence of a blockade and challenge the legal authority of the party which has undertaken to establish it.

2 One belligerent, engaged in actual war, has a right to blockade the ports of the other, and neutrals are bound to respect that right.

3 To justify the exercise of this right and legalize the capture of a neutral vessel for violating it, a state of actual war must exist, and the neutral must have knowledge or notice that it is the intention of one belligerent to blockade the ports of the other.

4. To create this and other belligerent rights, as against neutrals, it is not necessary that the party claiming them should be at war with a separate and independent power: the parties to a civil war are in the same predicament as two nations who engage in a contest and have recourse to arms.

5. A state of actual war may exist without any formal declaration of it by either party, and this is true of both a civil and a foreign war.

6. A civil war exists and may be prosecuted on the same footing as if those opposing the Government were foreign invaders, whenever the regular course of justice is interrupted by revolt, rebellion, or insurrection so that the Courts cannot be kept open.

7. The present civil war between the United States and the so-called Confederate States, has such character and magnitude as to give the United States the same rights and powers which they might exercise in the case of a national or foreign war; and they have, therefore, the right jure bello to institute a blockade of any ports in possession of the rebellious States.

8. The proclamation of blockade by the President is of itself conclusive evidence that a state of war existed, which demanded and authorized recourse to such a measure.

9. All persons residing within the territory occupied by the hostile party in this contest, are liable to be treated as enemies, though not foreigners.

10. It is a settled rule, that a vessel in a blockaded port is presumed to leave notice of a blockade as soon as it commences.

11. The proclamation of blockade having allowed fifteen days for neutrals to leave, a vessel which overstays the time is liable to capture although she was prevented by accident from getting out sooner.

12. To make a capture lawful, it is not necessary that a warning of the blockade should have been previously endorsed on the register of the captured vessel.

How the Justices Voted

Majority: Grier, joined by Wayne, Swayne, Miller, Davis

Dissent: Nelson, joined by Taney, Catron, Clifford