Can The President Unilaterally Declare An Invasion?

Or can only Congress declare an invasion, like Congress has the sole power to declare war?

In my post on the invasion executive order, I wrote "I think it pretty clear that the President can declare an invasion." A reader opined that because Congress has the power to declare war, the President cannot unilaterally declare an invasion. Relatedly, a reporter asked me if a President has ever before declared an invasion.

I think the general consensus view is that for the President to use military power abroad as part of a war, Congress must declare war. (There is some debate about whether a declaration is needed for something less than a war, such as "hostilities," but I'll table that issue for now.) I also think the general consensus view is that the President does not need a declaration of war to repel an invasion. That is, if the United States is under attack, the President can act to secure the homeland before seeking authorization from Congress. And if the President can repel an invasion, then he necessarily has the power to declare when such an invasion is occurring.

Thankfully, the United States has suffered very few invasions. Our conflicts generally have been fought abroad. A few of the more prominent invasions would be the War of 1812 and Pearl Harbor. In both conflicts, Congress issued declarations of war against Great Britain and Japan, respectively. On short notice, I could not find anything from President Madison that is relevant for the War of 1812. But I find relevant President Franklin D. Roosevelt's "Day of Infamy" speech, delivered on December 8, 1841. This speech asked that Congress declare war between the United States and Japan. Yet, FDR had already determined that Japan invaded the United States. He spoke to the invasion directly:

"No matter how long it may take us to overcome this premeditated invasion, the American people in their righteous might will win through to absolute victory."

I do not know if Roosevelt was able to dispatch any orders to Pearl Harbor during the attacks. But let's assume that communications were different. Does anyone doubt that Roosevelt could have ordered troops at Pearl Harbor to fight back against the invading Japanese Kamikazes? I think the answer is yes, because the President has the Article II authority to repel an invasion. What is the alternative? Would FDR have to convene Congress and wait for a declaration to stop an impending attack?

If that analysis is right, where would that declaration of invasion leave Hawaii? (Assume for a moment that Hawaii was a state in 1941). Article I, Section 10, Clause 3 provides that a state can "engage in War" when "actually invaded." If President Roosevelt declared that Hawaii was being invaded, the Executive of Hawaii could have "engaged in War" against the incoming attack. I do not know that Hawaii even had the apparatus of war, but that is a separate question.

In 1942, several Nazi saboteurs landed on the beach in Long Island. I would think that these were invading forces. By this point, war had already been declared against Germany, so a declaration of invasion would not have been necessary. For whatever it is worth, the Supreme Court in Ex Parte Quirin (1942) referred to such forces a "enemy invaders."

Also relevant is an incident from Texas in 1874. Judge Ho described it in his United States v. Abbott concurrence:

These issues came to a head in 1874. The United States Attorney General informed Texas Governor Richard Coke that his military orders violated a federal statute prohibiting unauthorized hostile actions in other countries. Id. at 164 (citing Act of April 20, 1818, § 6, 3 Stat. 449). Governor Coke responded by invoking his constitutional authority under Article I, section 10. See id. at 164–67 (text of letter available in the Appendix). In doing so, he acknowledged that federal authorities had the "power" to obstruct his actions if they wanted to. Id. at 167. After all, the United States possesses superior military forces, as well as the authority to call state militias into federal service (U.S. Const. art. I, § 8, cl. 15–16; id. art. II, § 2, cl. 1). But he explained his "clear conviction[]" that, notwithstanding federal law, States have the same "right" to self-defense that would "ordinarily reside in the United States." Id. at 166–67. In response, the Attorney General acquiesced to the Governor's claim of authority. Id. at xvi.

Here, the executive branch acquiesced to the declaration of an invasion by Texas.

There are three other relevant references to invasion in the Constitution.

First, Congress has the power "To provide for calling forth the Militia to execute the Laws of the Union, suppress Insurrections and repel Invasions." But the President, as Commander in Chief of the Militia, has the power to decide when to call forth the Militia to accomplish those ends. I would think that the President can decide when there is an insurrection or invasion at hand, in order to call forth the Militia. This argument is supported by the Militia Act of 1795.

It provides, in part:

That whenever the United States shall be invaded, or be in imminent danger of invasion from any foreign nation or Indian tribe, it shall be lawful for the President of the United States to call forth such number of the militia of the state, or states, most convenient to the place of danger, or scene of action, as he may judge necessary to repel such invasion, and to issue his orders for that purpose, to such officer or officers of the militia, as he shall think proper. Act of February 28th, 1795 (1 Stat. at Large, 424).

In Martin v. Mott (1827), Justice Story described this provision:

If we look at the language of the act of 1795, every conclusion drawn from the nature of the power itself, is strongly fortified. The words are, 'whenever the United States shall be invaded, or be in imminent danger of invasion, &c. it shall be lawful for the President, &c. to call forth such number of the militia, &c. as he may judge necessary to repel such invasion.' The power itself is confided to the Executive of the Union, to him who is, by the constitution, 'the commander in chief of the militia, when called into the actual service of the United States,' whose duty it is to 'take care that the laws be faithfully executed,' and whose responsibility for an honest discharge of his official obligations is secured by the highest sanctions. He is necessarily constituted the judge of the existence of the exigency in the first instance, and is bound to act according to his belief of the facts.

It would seem here that Congress has authorized the President to determine when an invasion occurs. And when he make such a declaration, Congress has authorized the President to call forth the militia. But the President does not need to seek a declaration from Congress before that power can be exercised. The President decides what is an invasion, and that decision is entitled to vast deference.

Second, Congress can suspend the Privilege of the Wit of Habeas Corpus "when in Cases of Rebellion or Invasion the public Safety may require it." Under Ex Parte Merryman, Congress has the sole power to suspend the writ of habeas corpus. At least with regard to suspending habeas corpus, it would seem Congress has the power of making such a determination. It would not be prudent for Congress to wait for the President to declare an invasion, especially since the President may be the person who is imprisoning people without any process.

Third, "The United States shall guarantee to every State in this Union a Republican Form of Government, and shall protect each of them against Invasion." This text does not specify the branch of the federal government that makes such a "guarantee." The "United States" usually refers to Congress assembled, rather than the executive branch. But in Luther v. Borden (1849), Chief Justice Taney wrote that whether a state has changed its government " is a question to be settled by the political power." And Taney says this power belongs to the President:

By this act, the power of deciding whether the exigency had arisen upon which the government of the United States is bound to interfere, is given to the President. He is to act upon the application of the legislature or of the executive, and consequently he must determine what body of men constitute the legislature, and who is the governor, before he can act. The fact that both parties claim the right to the government cannot alter the case, for both cannot be entitled to it. If there is an armed conflict, like the one of which we are speaking, it is a case of domestic violence, and one of the parties must be in insurrection against the lawful government. And the President must, of necessity, decide which is the government, and which party is unlawfully arrayed against it, before he can perform the duty imposed upon him by the act of Congress. . . .  It is said that this power in the President is dangerous to liberty, and may be abused. All power may be abused if placed in unworthy hands. But it would be difficult, we think, to point out any other hands in which this power would be more safe, and at the same time equally effectual.

Luther concerned an insurrection, rather than an invasion. But Taney said there was no difference between the two, at least with regard to the Militia Act:

A question very similar to this arose in the case of Martin v. Mott, 12 Wheat. 29–31. The first clause of the first section of the act of February 28, 1795, of which we have been speaking, authorizes the President to call out the militia to repel invasion. It is the second clause in the same section which authorizes the call to suppress an insurrection against a State government. The power given to the President in each case is the same,—with this difference only, that it cannot be exercised by him in the latter case, except upon the application of the legislature or executive of the State.

Where does this history leave us.

The Constitution expressly grants Congress the power to declare war, but does not indicate which branch of government can declare an invasion. The general understanding is that Article II grants the President the power to repel an invasion, and presumably, the President can determine when such an invasion is occurring. The Militia Act of 1795 supports the presumption. The Constitution allows Congress, and not the executive, to suspend habeas corpus during an invasion, which would require Congress to determine when there is an invasion.

Is the power to declare an invasion, like the power to declare war, reserved solely to Congress? Or is the Constitution silent on this issue, and might permit both Congress and the President to make this determination? My initial inclination was the latter, and having thought this issue through, I think this is the better answer. But there is so little law here, and so few invasions, there is not much to go on. My thoughts here are tentative, and I welcome comments and corrections.

I heard a report that members of Congress may vote to declare an invasion, so this issue may become moot.