How 9/11 and the War on Terror Led to the Expansion of Executive Power

I. Introduction

The terrorist attacks of 9/11 reshaped American political institutions and triggered one of the most significant expansions of executive power in U.S. history. Scholars explain this expansion in different ways, emphasizing the roles of legal structures, bureaucratic developments, and presidential rhetoric in shaping the post-9/11 security landscape. This review synthesizes how the War on Terror altered federal authority by examining where scholars agree, where they disagree, and what their arguments collectively reveal about the growth of executive power. Together, the literature demonstrates that 9/11 fundamentally transformed the political and institutional foundations of the American government.

II. Institutional Transformation

Peter Amato argued in the Notre Dame Journal of Legislation that the Authorizations for Use of Military Force (AUMFs) drastically expanded presidential war-making powers. AUMFs are laws giving the president the power to use "all necessary and appropriate force"¹ without a formal declaration of war. This expansion was because Congress had "taken no effective action to curb executive power in the misuse of the AUMFs"² in the ongoing application of the AUMFs. As a result, administrations were able to stretch the meaning of the AUMFs beyond their original intention of authorizing a limited, Congress-approved response to threats after 9/11, leading to expanded executive power.

Ingber builds on Amato's critique by taking a deeper dive into the effects of the expansion of power in the executive branch. Executive power was able to expand through bureaucratic interpretation, and agencies began to reinterpret statutes such as the AUMF to justify uses of executive force. According to Ingber, these actors used bureaucratic interpretation to reshape laws like the AUMF over time, giving the executive branch more power through small, incremental changes rather than major political decisions.³ Both Amato and Ingber argue that the AUMF played a huge role in growing executive authority, but Ingber goes further by showing how executive-branch lawyers and agencies stretched laws like the AUMF far beyond what Congress originally meant.⁵

Swalwell and Alagood add another perspective by explaining how 9/11 led to major institutional growth across the federal government. The creation of the Department of Homeland Security exemplifies this growth, as it absorbed 22 agencies and expanded domestic surveillance, permanently changing the government's role in national security.⁴ Although these institutions were first built to fight al-Qaeda, they eventually shifted toward monitoring domestic extremist threats. Together, their research highlights that post-9/11 structures and laws were flexible enough to grow far beyond their original purpose, creating a long-lasting increase in executive authority.⁶

III. Presidential Rhetoric

Ristevska and Prezelj argue that presidential involvement is what essentially led to the expansion of executive authority. Presidential speeches significantly influenced public attitudes toward terrorism and contributed to the normalization of stronger executive authority. According to their study, Obama and Biden relied on techniques such as balanced framing and more restrained approaches compared to Trump and Bush, who focused on scrutiny and fear.⁷ Despite the different approaches, all four presidents still kept the same counterterrorism powers in place.

Swalwell and Alagood support this idea by showing how the meaning of "terrorism" shifted over time. Post-9/11 presidents changed the narrative by using counterterrorism tools that were originally designed for foreign threats and applying them to domestic extremist dangers, which eventually became the main security concern.⁸ This shows how presidential rhetoric shifts to match new threats over time, helping strengthen and justify the growth of executive power.

Amato supports this rhetoric using the congressional debates regarding AUMFs and how fear-based political messaging makes Congress hesitant to revise old war-making laws like the AUMF. Framing techniques have also affected legislative incentives and reinforced executive flexibility.⁹ The International Crisis Group adds that repeated congressional reluctance to repeal or amend open-ended laws has converted post-9/11 emergency measures into permanent policy foundations. The Crisis Group additionally adds that presidents' public rationale directly encouraged the executive to lead and expand militarized counterterrorism operations at home and abroad because "the statute does in reality give the president a worldwide writ to use force against the groups and individuals deemed by him or her to fall within its ambit."¹⁰

These operations were justified and normalized through presidential rhetoric, often making the war on terror seem necessary, regardless of the threat shifting from abroad to domestic. The analysis shows how framing not only established legitimacy for executive action, but also discouraged Congressional limits or reforms because of the stretching of laws.¹¹ The Crisis Group further highlights how presidential narratives keep counterterror operations politically viable and protect the executive branch from oversight or lasting reform.¹² Lastly, Amato provides the political consequences, such as rhetorical pressure that discourages Congress from revising old war-making laws.¹³

IV. Conclusion

The literature demonstrates that the post-9/11 expansion of executive power actually led to a long-term structural transformation of the government rather than a temporary reaction to a crisis. Legal ambiguity, bureaucratic interpretation, institutional growth, and presidential framing have fundamentally altered the legal and political foundations of American governance post-9/11.