The Prize Cases (p. 367)

 

Under Article I, section 8, "The Congress [not the President] shall have Power...to declare War."

 From Oyez:

Facts of the case

Lincoln proclaimed a blockade of southern ports in April 1861. Congress authorized him to declare a state of insurrection by the Act of July 13, 1861. By the Act of August 6, 1861, Congress retroactively ratified all Lincoln's military action. These cases involved the seizure of vessels bound for Confederate ports prior to July 13, 1861.

Question

Did Lincoln act within his presidential powers defined by Article II when he ordered the seizures absent a declaration of war?

 

Holding

The President had the power to act. A state of civil war existed de facto after the firing on Fort Sumter (April 12, 1861) and the Supreme Court would take this fact into account. Though neither Congress nor the President can declare war against a state of the Union, when states waged war against the United States government, the President was "bound to meet it in the shape it presented itself,without waiting for Congress to baptize it with a name." See casebook p. 367-368.

 Chemerinsky explains the cases this way:

"[T]he Court ruled that the president had the power to impose a blockade on Southern states without a congressional declaration.The Court spoke broadly of the president's power to respond to invasions or rebellions" 'If a war be made by invasion of a foreign nation, the president is not only authorized but bound to 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 nonetheless a war, although the declaration of it be unilateral.'"