“A republic, if you can keep it.” – Benjamin Franklin

On the night of December 3, 2024, South Korean President Yoon Suk Yeol shocked the international stage by declaring emergency martial law. This was the first time martial law was declared since 1980 before South Korea was freed from military rule and democratized in 1988. As a result, all political activities were banned, in addition to government restrictions on the freedom of speech and press. Anyone found violating the proclamation could be “arrested, detained, and searched without a warrant.” Active-duty soldiers and police officers were sent to take control of various targets including the National Assembly and the National Election Commission. 

Under Article 77 of the South Korean Constitution, the President does have the power to declare martial law “in time of war, armed conflict or similar national emergency.” However, there was no foreign invasion. Instead, President Yoon claimed that the opposing Democratic Party of Korea—which holds the majority in the National Assembly—was a threat to the nation because of their efforts to impeach members of his cabinet and push budget cuts that allegedly “paralyze” the government. He called the National Assembly “a den of criminals” and swore to “eradicate the shameless pro-North anti-state forces”. 

The declaration did not last long. Resistance from South Korean citizens and hesitancy from the deployed troops in enforcing the decree allowed 190 of 300 lawmakers to enter the National Assembly and vote unanimously to lift martial law. Under Section 5 of Article 77, President Yoon was forced to comply, and the situation was resolved in approximately six hours after his initial address to the nation. Yoon was later impeached and arrested on charges of insurrection. 

On April 4th, 2025, the Constitutional Court unanimously upheld Yoon’s impeachment, forcing him out of office and starting a 60-day countdown to elect a new president. While the democratic process managed to endure, South Korea is still plagued by political division. 

But the fact that South Korea has been one of the most successful examples of democracy in Asia begs the question: is the United States—as one of the most stable democracies in the world—safe from the abuse of military power? In recent years, legal scholars have argued that the Insurrection Act—which allows the President to use active-military personnel for domestic law enforcement during emergencies—may lead to an abuse of executive power due to its ambiguities (10 U.S.C.A. § 251-255). 

This article will argue in favor of reforming the Insurrection Act by placing additional restrictions on its power. I will derive these restrictions from the legal limits of U.S. martial law addressed in Duncan v. Kahanamoku (1946). Although activating the Insurrection Act is not equivalent to the declaration of martial law, I would argue that the legal limits of martial law nevertheless provide comprehensive guidelines for the role of the military in domestic law enforcement, even during emergencies. 

The Insurrection Act

The Insurrection Act was signed into law by Jefferson in 1807, which was intended to address an armed plot against the United States led by Aaron Burr. Since then, the emergency power has been activated several times throughout history and maintains its relevance today. Most recently, Section 6(b) of the executive order titled “Declaring a National Emergency at the Southern Border of the United States” by President Trump states,

Within 90 days of the date of this proclamation, the Secretary of Defense and the Secretary of Homeland Security shall submit a joint report to the President about the conditions at the southern border of the United States and any recommendations regarding additional actions that may be necessary to obtain complete operational control of the southern border, including whether to invoke the Insurrection Act of 1807.

But in most situations, the U.S. military cannot be deployed for domestic law enforcement due to the Posse Comitatus Act, now known as 18 U.S.C.A. § 1385:

Whoever, except in cases and under circumstances expressly authorized by the Constitution or Act of Congress, willfully uses any part of the Army, the Navy, the Marine Corps, the Air Force, or the Space Force as a posse comitatus or otherwise to execute the laws shall be fined under this title or imprisoned not more than two years, or both.

The exception Congress granted to the President is the Insurrection Act (10 U.S.C.A. § 252):

Whenever the President considers that unlawful obstructions, combinations, or assemblages, or rebellion against the authority of the United States, make it impracticable to enforce the laws of the United States in any State by the ordinary course of judicial proceedings, he may call into Federal service such of the militia of any State, and use such of the armed forces, as he considers necessary to enforce those laws or to suppress the rebellion.

However, the Insurrection Act poses two potential threats to the balance of power due to its vague language. 

First, the President is given sole discretion in determining when it is appropriate to use the Insurrection Act, leaving Congress with no checks on the executive branch on this matter. This is in stark contrast to the War Powers Resolution, which placed major restrictions on the President’s authority to deploy the Armed Forces abroad. This resolution passed into law in 1973, overriding Nixon’s veto. Under this resolution, if Congress did not declare war, the President must report to the Speaker of the House and President pro tempore of the Senate within 48 hours after choosing to deploy the Armed Forces. Furthermore, if the President does not receive any congressional approval, the unilateral deployment of the Armed Forces must be terminated after 60 days. 

Second, the Insurrection Act enables the President to use whatever means that he determines necessary to enforce the law. In other words, the President practically acquires a blank check on domestic law enforcement, even when using the military to do so. 

The Legal Limits of Martial Law and Their Application to the Insurrection Act

No legislation by Congress explicitly indicates that the President, or any branch of the federal government, has the authority to declare martial law, nor is it ever mentioned in the Constitution. Regardless, the U.S. Supreme Court has previously recognized the legality of martial law. 

Following America’s independence from Britain, the state of Rhode Island was still governed by a 1663 royal charter from King Charles II, not a state constitution. When some Rhode Islanders took it upon themselves to form a new government under a constitution, the preexisting state General Assembly rejected its legitimacy and declared martial law in 1842 to quell the new government. The Court upheld Rhode Island’s use of martial law in Luther v. Borden (1849), declaring that “if the government of Rhode Island deemed the armed opposition so formidable, and so ramified throughout the State, as to require the use of its military force and the declaration of martial law, we see no ground upon which this court can question its authority.”

The most recent Court ruling on the use of martial law was Duncan v. Kahanamoku (1946). At the time, Hawaii was still a U.S. territory governed under the Hawaiian Organic Act from 1900, which does explicitly allow its governor to “suspend the privilege of the writ of habeas corpus, or place the Territory, or any part thereof, under martial law until communication can be had with the President…” if he saw it necessary for “public safety.” 

In 1941, after the events of Pearl Harbor, Governor Joseph Poindexter placed the Hawaiian territory under martial law, largely due to its proximity to Japan and concerns of loyalty about its large Japanese-American population. As a result, Lloyd Duncan—a civilian—was arrested, tried, and convicted at a military tribunal for assaulting two Marines. Although the Court again upheld the legitimacy of martial law, it nevertheless ruled in favor of Duncan, declaring that martial law under the Hawaiian Organic Act “was not intended to authorize the supplanting of courts by military tribunals.”

There are three key takeaways from ​​Duncan v. Kahanamoku, which are also supported by previous Supreme Court cases:

First, the Supreme Court has the authority to determine the legal boundaries of the military. Duncan v. Kahanamoku is a clear example of judicial review that declared certain actions of the military to be unconstitutional. In Ex parte Milligan (1866), the Supreme Court ruled that the legal suspension of the writ of habeas corpus did not allow civilians to be tried in a military tribunal when civil courts were available. 

Second, there is no scenario in which the military is permitted to ignore the Constitution or any other civilian law. Citing Dow v. Johnson (1879), the Court declares in Duncan v. Kahanamoku that “the military should always be kept in subjection to the laws of the country to which it belongs, and that he is no friend to the Republic who advocates the contrary. The established principle of every free people is, that the law shall alone govern; and to it the military must always yield.” The Court noted that the territory of Hawaii is not exempt from the protections of the Constitution, implying that the Constitution remains the supreme law of the land for both civilians and the military. 

Third, the military is permitted to enforce the law only where the crisis is present and when the civilian courts cease to function. Citing Ex parte Milligan (1866), the Court notes that “civil liberty and this kind of martial law cannot endure together; the antagonism is irreconcilable; and, in the conflict, one or the other must perish.” The ruling for Ex parte Milligan also notes that “[a]s necessity creates the rule, so it limits its duration; for, if this government is continued after the courts are reinstated, it is a gross usurpation of power. Martial rule can never exist where the courts are open, and in the proper and unobstructed exercise of their jurisdiction. It is also confined to the locality of actual war.” In other words, martial law is intended to be a method of last resort for domestic law enforcement. 

Although Duncan v. Kahanamoku (and its preceding cases) was ruled in the context of martial law, it is worth noting that these restrictions are not unique to martial law, but can also apply to the broader role of the military in domestic affairs. I would argue that if a declaration of martial law does not allow the military to override judicial review and ignore the protections of the Constitution, it also cannot do so under the Insurrection Act. In other words, all Americans—both civilians and the military—are required to observe the Constitution in all situations, including national emergencies. 

I would propose four restrictions to be explicitly written into the Insurrection Act:

First, any invocation of the Insurrection Act must fall under judicial review. In the United States, no one is above the law. To suggest that the President can have limitless discretion in times of crisis implies that the President is in fact, above the law in certain situations. If the Court can declare certain actions of the government to be unconstitutional even when those actions were completed under martial law, the Court can declare certain actions of the President to be unconstitutional even after the Insurrection Act was invoked. 

Second, the President may not order the military to violate any law protected by the Constitution, including due process and the writ of habeas corpus. This is where invoking the Insurrection Act must be held under stricter restrictions than a declaration of martial law. Unlike martial law, which involves limits on several rights including the freedom of speech and press, nothing in the Insurrection Act explicitly permits the President to violate these rights. In other words, the Insurrection Act allows the President to use the Armed Forces only as a supplement for domestic law enforcement to “enforce the laws of the United States” when traditional law enforcement fails to do so. The President cannot use the legislation as a loophole to bypass the Constitution.

Third, much like how martial law must be “confined to the locality of actual war” under Ex parte Milligan, the powers of the Insurrection Act must be confined to the location of the crisis. To deploy the armed forces where domestic law enforcement has not failed would be the usurpation of civilian law. 

Finally, any abuse of the Insurrection Act can be held responsible under the impeachment process. Much like other violations of the Constitution, if Congress judges that the President has overstepped the boundaries of executive authority, it can use the impeachment process to remove the President from office. For example, if the President instructs the Armed Forces to seize control of Congress when no armed rebellion exists there, it would be an act of treason and grounds for impeachment. 

While it may seem that the proposed reforms are already implied within the Insurrection Act, we cannot allow even the smallest possibility of misinterpreting such a potent emergency power in order to abuse the powers of the executive branch. As it stands, the vague language of the Insurrection Act grants the President the authority to quell any perceived crisis using practically any means that the President deems necessary. To allow a single individual to serve as judge, jury, and executioner of U.S. law is a dangerous loophole in the Constitution. 

Briefly Addressing an Objection to the Calls to Reform the Insurrection Act

Some defend the Insurrection Act with the argument that the Supreme Court has already granted the President the discretion to determine the appropriate use of the Insurrection Act. This argument is derived from Martin v. Mott (1827), where the Court declared that “the authority to decide whether the exigency has arisen, belongs exclusively to the President, and that his decision is conclusive upon all other persons”. 

While this is correct, the objection misses the point. In Sterling v. Constantin (1932), the Court affirmed that “the executive is appropriately vested with the discretion to determine whether an exigency requiring military aid for that purpose has arisen.” However, they also noted that “it does not follow from the fact that the executive has this range of discretion, deemed to be a necessary incident of his power to suppress disorder, that every sort of action the Governor may take, no matter how unjustified by the exigency or subversive of private right and the jurisdiction of the courts, otherwise available, is conclusively supported by mere executive fiat.” In other words, while the executive has the sole authority to decide when a crisis requires the invocation of the Insurrection Act, it does not grant the President limitless power in handling that crisis.

Although Sterling v. Constantin was concerning state governors, it is also clear that the President does not have unlimited power during emergencies. In Ex parte Milligan, the Court declared President Lincoln’s use of military tribunals unconstitutional; while the suspension of the writ of habeas corpus may have been legally justified, “the Constitution goes no further”. In Youngstown Sheet & Tube Co. v. Sawyer (1952), the Supreme Court struck down President Truman’s seizure of steel mills during the 1952 steelworker strikes, declaring that “the President’s power to see that the laws are faithfully executed refutes the idea that he is to be a lawmaker.”

Final Thoughts

The recent South Korean martial law crisis serves as a clear warning to democracies across the world of the potential dangers in allowing the military to have an excessive role in the political process. In all domestic affairs, the military must be a means of last resort, not a means of convenience or political advantage. It is worth noting that President Yoon’s declaration of martial law was not halted by him, but by the National Assembly, the people, and the South Korean Constitution. After his impeachment, he also attempted to delay the legal process and resisted arrest. He denied any wrongdoing and claimed that his declaration of martial law was legitimate and not an attempted coup. It was not until the Constitutional Court upheld his impeachment Yoon was finally forced out of office. In the aftermath of the martial law crisis, several proposals have been brought to the National Assembly to reform or even repeal the President’s authority to declare martial law.

Any president of the United States has the means to seize excessive emergency powers in potentially inappropriate circumstances by invoking the Insurrection Act. The legislation requires explicit legal guardrails, not just executive goodwill.