An International Law Perspective on the U.S.’s Recent Strikes in International Waters

Written by Lily Fernandez

November 19, 2025

*While the situation between the United States and Venezuela has since escalated, this blog post analyzes the United States’ military strikes on international vessels as of November 19, 2025, as a separate violation of international law and thus does not touch on the capture and arrest of Venezuelan leader Nicolás Maduro.

Introduction

The United States has carried out twenty deadly strikes against vessels in international waters since September 2025.¹ In total, these strikes have killed at least eighty individuals.² Prior to the attacks, the Trump administration declared several drug cartels, including the Venezuelan gang Tren de Aragua, to be unlawful combatants.³ Following the attacks, the administration announced a “non-international armed conflict” with these cartels.⁴ The Trump administration used these designations as justification for the strikes on vessels in the Caribbean, accusing the individuals of being drug traffickers.⁵ In a letter from President Trump to the President pro tempore of the Senate, the President stated that the strikes were acts of self-defense because “[e]xtraordinarily violent drug trafficking cartels that the United States has designated as terrorist organizations have wrought devastating consequences on American communities . . . . [W]e must meet this threat . . . with United States military force in self-defense.”⁶ By claiming the attacks were acts of self-defense, Article 51 of the U.N. Charter would preclude the unlawfulness of the United States’ military action.⁷

While these attacks raise numerous issues under international and domestic law, this piece will focus on whether the United States can properly rely on Article 51’s self-defense clause as justification for these attacks, whether drug trafficking is an “armed attack” worthy of invoking the Article, and whether the Article’s procedural aspects create the opportunity for states to falsely claim self-defense. Ultimately, the United States’ strikes cannot be justified through self-defense because the cartels did not commit an armed attack against the United States, despite their designation as unlawful combatants.

Background

After the first strike on September 2, 2025, President Trump justified the attack by claiming self-defense under Article 51 of the U.N. Charter, which allows the use force that would otherwise violate the Charter in response to an “armed attack.”⁸ As Steven Ratner notes, what qualifies as an armed attack is a highly contested question.⁹ The historical understanding required military force for an action to be considered an armed attack.¹⁰ However, due to the nature of modern terrorist organizations, that idea has less effect in practical application.¹¹

A non-state actor, in the context of terrorist organizations, is an entity that exercises significant political and territorial power, is outside the control of a sovereign government, and often employs violence in pursuit of its objectives.¹² Although Article 51 of the U.N. Charter is an obligation between states, the International Court of Justice (ICJ) has concluded that an armed attack can be committed by a non-state actor, and therefore ought to be judged on the same scale.¹³

Analysis

While there is not one set definition of an armed attack, the ICJ and other international organizations agree that armed attacks are the “most grave forms of a use of force.”¹⁴ Despite the contention over defining the term, the harm done to the United States by the cartels does not constitute an armed attack, and the United States’ designation of the cartels as terrorist groups does not justify the use of Article 51.

The legal determination of whether drug trafficking can constitute an armed attack worthy of self-defense is difficult to predict, partially due to the lack of a clear interpretation of armed attack. Some legal scholars believe that the aforementioned cartels were not engaged in hostilities grave enough to constitute an armed attack because selling a dangerous product to willing consumers does not rise to the requisite level of the gravest use of force against a nation.¹⁵ A dangerous substance, while harmful, is likely not a direct use of force against the United States because it does not involve military action, the government has little to no involvement, and the weapon which would be constituting this armed attack is the wide sale of drugs, not equipment which can be used in violent attacks.¹⁶ The ICJ has noted the threshold of an armed attack as scale and effects, meaning a nation ought to be able to defend itself against an armed attack when the scale and effect of the attack warrant it.¹⁷ Scale and effect are determined by the target of the attack, the number and type of weapon used in the attack, and the duration.¹⁸ This indicates that, despite the wide-spread damage caused by these dangerous substances, drug trafficking, primarily because of the lack of weapons used, is not an armed attack. Should it be determined that an armed attack did not occur, the United States will not be able to claim self-defense as justification for its attacks. Proponents of deeming drug trafficking by cartels an armed attack worthy of self-defense argue that the scale and effects ought to way in favor of self-defense, however, the ICJ has traditionally stressed the requirement for the use of weapons in an armed attack, and, further, the ICJ has noted that the action in response must be proportional to the attack.¹⁹ Here, if drug trafficking could be considered an armed attack, military strikes on both civilian and military boats in response is disproportionate.

The Trump administration’s declaration of these cartels as terrorist organizations adds a layer of complexity because terrorist attacks are often deemed to be armed attacks warranting self-defense.²⁰ But the acts of the cartels can likely not be considered terrorist attacks because they lack the requisite intent the U.N. Security Council wrote into the definition.²¹ The Council defines terrorist activity as criminal acts that are committed with the intent to cause death or with the purpose to provoke a state of terror in the public.²² Despite the destruction caused by cartels, it would be difficult to prove that the organizations intended to cause terror in the general population because cartels are recognized as being motivated by financial profit, not religious or ideological extremism.²³ The Trump administration, however, was able to designate several cartels as foreign terrorist organizations under a broad statutory definition which includes organizations that are financially motivated, rather than politically or religiously motivated, in the umbrella of terrorist organizations.²⁴ But their mere classification as such does not raise the level of their actions to an armed attack.

Article 51 of the U.N. Charter is frequently invoked by states, at least seventy-eight times since 2021.²⁵ Examples include Russia’s invocation in defense of its attack on Ukraine, Israel’s claim of self-defense against Hamas, and the United States’ claim of self-defense for its attack on Iranian nuclear bunkers.²⁶ These examples highlight the potential for abuse of Article 51. The procedure of invoking the Article may be a part of the cause of the abuse. Article 51 requires the State to inform the U.N. when it takes an action in self-defense.²⁷ However, the report is largely up to the reporting State because there are no requirements on what must be included.²⁸ Due to the minimal regulation and oversight over the procedure of invoking Article 51, too much discretion is left to the invoking States. This discretion allows a State to excuse its actions as self-defense with little-to-no intervention by the United Nations.

Conclusion

The United States’ strikes against the Venezuelan vessels likely do not meet the requirements to invoke Article 51 because the cartels involved did not commit an armed attack on the United States by distributing a dangerous substance to the public, despite the United States’ declaration of the cartels as terrorist organizations. However, the procedure involved in invoking Article 51 allows the invoking party ample discretion and leads to inconsistent application, enabling states to claim self-defense without proper review. Allowing the United States to characterize drug trafficking as an armed attack sets a dangerous precedent that untethers self-defense from its foundational requirement of the gravest form of violence. Should this be left unchecked, this incites other states to abuse the self-defense exception, furthering uses of force against other nations.

Posted in Blog

Written by Lily Fernandez

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