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  • Writer's pictureLaking Harris

The Unchecked Constraints of Self-Defense: Implications for International Law

In the wake of the September 11, 2001 terrorist attacks, the United States embarked on a journey that few could have anticipated would extend for over two decades. What began as a response to those tragic events has led to ongoing military operations not just in Afghanistan but across the Middle East and much of Africa. While the causes behind this prolonged state of war are multifaceted, some of the blame can be attributed to evolving legal interpretations. This blog post delves into two critical legal interpretations that have played a pivotal role in perpetuating perpetual warfare: the erosion of domestic constraints on presidential war powers and the ever-expanding reliance on the international law concept of "self-defense." Together, these interpretations have significantly reduced legal restrictions on the use of military force by the U.S. president, posing risks to both domestic and global legal orders.

The Erosion of Congressional Constraints on War Powers

Over the last century, presidential war powers in the United States have grown to the point where the president effectively holds unilateral authority over military force decisions, especially when ground troops are not significantly deployed. Shockingly, the U.S. Congress has not granted approval for the use of military force since 2002, when it authorized the invasion of Iraq. Despite this lack of explicit authorization, the United States remains embroiled in multiple conflicts, including ongoing military engagements in Afghanistan, Iraq, Somalia, Yemen, Syria, and Libya.

Self Defense
self Defense

The erosion of effective congressional constraints on presidential war powers can be traced back to a crucial decision in the War Powers Resolution, which tied reporting requirements and automatic withdrawal provisions not to "war" or "armed conflict" but to the vague term "hostilities." This ambiguity has allowed for differing interpretations, further exacerbated by the reluctance of the courts to intervene. As a result, the executive branch has become the primary source of public legal opinions on war powers, leaving the president virtually unconstrained in waging wars abroad.

The Rise & Constraints of "Self-Defense"

One significant consequence of the erosion of congressional war powers is the broadening of the right to "self-defense" under international law. The United States, with its influential role and assertive legal positions, has played a pivotal role in expanding this concept, not only for itself but for the broader international community.

Article 51 of the United Nations Charter originally created a narrow exception for individual and collective self-defense in cases of an "armed attack" by one state against another. However, the U.S. and other states have progressively stretched the interpretation of this exception. Notably, the "Bush Doctrine" asserted that preemptive action could be taken in response to a "sufficient threat to national security," even if an attack was not imminent. This doctrine continued to influence subsequent administrations, including the Obama administration.

Furthermore, the expansion of self-defense to include actions against non-state actors has become a significant development. Before 9/11, self-defense under Article 51 was generally believed to apply only to state-to-state scenarios. However, post-9/11, non-state aggressors have increasingly become the targets of self-defensive force, and the notion of "unwilling or unable" states has been introduced, justifying action against non-state threats in states that fail to suppress them.

The United States has also claimed that "collective self-defense" extends to actions in defense of non-state actor partners, which is a novel interpretation of international law. This expansion of the self-defense concept, especially in the context of non-state actors, has far-reaching implications for global understanding and application of self-defense under international law.


The ongoing debate over the reform of war powers and the reassertion of congressional authority over military decisions has not only domestic but also international repercussions. Reestablishing congressional war powers is vital for preventing further expansion of self-defense claims made by successive U.S. presidents. It is a matter of constitutional law and international law, with implications not only for U.S. actions but also for the behavior of other states that may adopt similar legal theories to justify actions that challenge global peace and security.

Restoring Congress's constitutional war powers could make it less likely for the United States to engage in military operations that violate the United Nations Charter. It demonstrates a commitment to the rule of law and serves as a counterpoint to states that engage in aggressive and unlawful wars without proper checks and balances.

Explore the full article to gain a deeper understanding of how evolving legal interpretations have shaped the landscape of self-defense and its impact on international law and global peace.

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