Case Study 2: The Post-9/11 Presidency — How a 60-Word Authorization Built a Quarter-Century of Executive Power

The morning that reset the constitutional baseline

On the morning of September 11, 2001, the United States was attacked. By that evening, the executive branch was already drafting authorities for the response. By September 14 — three days after the attacks — Congress had passed Senate Joint Resolution 23, the Authorization for Use of Military Force (AUMF). The resolution ran sixty words. It authorized the president to use "all necessary and appropriate force against those nations, organizations, or persons he determines planned, authorized, committed, or aided" the September 11 attacks, and against any nation or person who "harbored such organizations or persons." Only one member of Congress — Representative Barbara Lee (D-CA) — voted against it.

Twenty-five years later, the AUMF 2001 is still operative. It has been invoked as the legal basis for combat operations in Afghanistan, Iraq, Yemen, Somalia, Pakistan, Libya, Syria, the Philippines, Niger, and elsewhere. It has been invoked against organizations that did not exist in 2001 — most notably the Islamic State, against which the Obama administration began operations in 2014 on the theory that ISIS was a successor to al-Qaeda in Iraq. It has been invoked under presidents of both parties, in geographies the 2001 Congress was not voting on, against threats that were not on anyone's radar in 2001.

This case study traces how the post-9/11 executive accumulated power across five administrations — Bush 43, Obama, Trump 1, Biden, Trump 2 — and how the Supreme Court, in a string of cases between 2004 and 2008, set partial but real limits. The point is not that any particular administration was wrong. The point is that the bipartisan continuity is the story. Democrats and Republicans, presidents who ran against the war-on-terror infrastructure and presidents who built it, have all operated within and extended the same framework.

What the executive built between 2001 and 2008

Within months of the AUMF's passage, the Bush administration constructed an interlocking set of authorities that constituted a new legal architecture for executive action.

Indefinite military detention. The Department of Defense began holding suspected enemy combatants — first at facilities in Afghanistan, then at Guantanamo Bay, Cuba, beginning in January 2002 — without trial, without charges, and without access to U.S. courts. The administration's position was that detainees were "unlawful combatants" not entitled to Geneva Convention protections and that the AUMF authorized their detention for the duration of hostilities, which could be indefinite.

Warrantless surveillance. The National Security Agency, under a presidential authorization signed in October 2001 and revealed publicly by The New York Times in December 2005, conducted electronic surveillance of communications between the United States and foreign locations without warrants from the Foreign Intelligence Surveillance Court (FISC). The administration's legal theory, articulated primarily by John Yoo at the Office of Legal Counsel, was that the AUMF and Article II's commander-in-chief power authorized surveillance that the Foreign Intelligence Surveillance Act (FISA) of 1978 had appeared to require warrants for.

Enhanced interrogation. The Department of Justice produced a series of memoranda — the "torture memos" — concluding that techniques including waterboarding, sleep deprivation, and stress positions did not constitute torture as defined by the federal anti-torture statute, and that even if they did, the president had inherent authority to authorize them under his commander-in-chief power. The CIA operated a classified network of "black sites" in foreign countries where high-value detainees were held and interrogated.

Targeted killing. A program of lethal strikes — initially by Predator drones, expanded under successor administrations — targeted specific individuals identified as members of al-Qaeda or associated forces. The first known strike of a U.S. citizen overseas (Anwar al-Awlaki, Yemen, 2011) occurred under Obama, not Bush.

The administration's overarching legal posture was that the AUMF was a broad authorization, that Article II conferred substantial inherent authority in wartime, and that judicial review of these activities was either unavailable or extremely deferential. This posture would be tested.

The Supreme Court pushes back

Three cases between 2004 and 2008 established that the post-9/11 executive could not operate beyond judicial review.

Hamdi v. Rumsfeld (2004). Yaser Esam Hamdi was a U.S. citizen captured in Afghanistan in 2001 and held without charges in a military brig in South Carolina. His father filed a habeas corpus petition. The Supreme Court ruled (8–1, with a plurality opinion by Justice O'Connor) that even in time of armed conflict, a U.S. citizen detained as an enemy combatant must receive notice of the factual basis for the detention and a meaningful opportunity to contest it before a neutral decisionmaker. O'Connor's plurality famously observed that "a state of war is not a blank check for the President." The AUMF, the Court held, authorized detention of enemy combatants captured on the battlefield — but did not authorize the elimination of due process for U.S. citizens. Hamdi was eventually transferred to Saudi Arabia after agreeing to renounce his U.S. citizenship.

Hamdan v. Rumsfeld (2006). Salim Ahmed Hamdan, a Yemeni national who had been Osama bin Laden's driver, was held at Guantanamo and slated for trial before a military commission established by presidential order. The Court ruled (5–3, with Chief Justice Roberts recused) that the military commissions, as constituted, violated both the Uniform Code of Military Justice and Common Article 3 of the Geneva Conventions. The Court rejected the administration's argument that the AUMF or the president's commander-in-chief power authorized commissions that did not meet basic procedural requirements. Congress responded by passing the Military Commissions Act of 2006, which attempted to provide statutory authorization for commissions on something closer to the administration's preferred terms.

Boumediene v. Bush (2008). The Military Commissions Act had purported to strip federal courts of habeas jurisdiction over Guantanamo detainees. The Court ruled (5–4, with Justice Kennedy writing the majority) that Guantanamo detainees had a constitutional right under the Suspension Clause (Article I, Section 9) to seek habeas corpus in federal court, and that the substitute review procedures Congress had provided were not adequate. Guantanamo, despite being on Cuban soil, was effectively under U.S. control, and the Constitution followed the flag where the United States exercised that kind of authority.

The three cases together established a constitutional baseline: even in the war on terror, even with broad AUMF authorization, the executive could not operate entirely outside judicial review, and detainees retained at least some procedural rights.

What the cases did not do is shut down the architecture. Detention continued — Guantanamo remained open through Bush, Obama, Trump 1, Biden, and Trump 2, with the population gradually declining but never reaching zero. Surveillance continued — Congress eventually amended FISA in 2008 (the FISA Amendments Act, providing statutory authorization for much of the previously warrantless program). Targeted killing continued and expanded. The infrastructure persisted; the courts adjusted its terms.

Bipartisan continuity from Obama through Trump 2

The story since 2008 is the steady normalization, across both parties, of the post-9/11 executive architecture.

Obama (2009–2017) entered office promising to close Guantanamo (executive order, January 2009) and to end the Bush-era detention and interrogation regime. The administration ended enhanced interrogation by executive order. Guantanamo did not close — Congress repeatedly blocked transfers to U.S. soil, and the Obama administration concluded that closing the facility was not a fight it could win. Drone strikes expanded substantially: more strikes were carried out under Obama than under Bush. The targeted killing of Anwar al-Awlaki (2011), an American citizen, generated a Justice Department legal memorandum (the so-called "white paper," partially leaked) defending the legality of the strike under the AUMF and under self-defense principles. The administration also expanded NSA surveillance authorities, an expansion partially revealed by the Edward Snowden disclosures in 2013. The 2014 expansion of operations against the Islamic State relied on the 2001 AUMF, on the theory that ISIS was a successor or affiliate of al-Qaeda — a theory many constitutional scholars regarded as strained but that the administration committed to legally.

Trump 1 (2017–2021) continued the architecture and added to it. The administration suspended new transfers out of Guantanamo. Drone strikes increased, with relaxed rules of engagement. The 2020 strike that killed Iranian general Qasem Soleimani in Iraq — a state actor, not a non-state combatant — relied on a combination of the 2002 AUMF and Article II self-defense authority; legal scholars across the spectrum questioned both bases. The administration also expanded surveillance authorities under FISA Section 702 reauthorization (2018).

Biden (2021–2025) completed the U.S. withdrawal from Afghanistan in August 2021 — ending the longest-running theater of post-9/11 combat operations. The withdrawal was chaotic; thirteen American service members and over a hundred Afghans died in a suicide bombing at Kabul airport. The administration continued counterterrorism operations elsewhere, including the strike that killed al-Qaeda leader Ayman al-Zawahiri in Kabul (July 2022). The administration supported a narrow Senate effort to repeal the 1991 and 2002 Iraq AUMFs (the Senate passed repeal in March 2023; the House did not act). The 2001 AUMF, the operative authority for almost all counterterrorism action, remained untouched.

Trump 2 (2025– ) has continued strikes in Yemen, Somalia, and elsewhere, and has expanded the use of emergency authorities for domestic immigration enforcement and tariff policy that draw on infrastructure originally built or expanded for counterterrorism. As of 2026, the 2001 AUMF remains the legal basis for ongoing operations.

What this case study illustrates

Three lessons.

The structural lesson. A broad authorization passed in a moment of crisis can persist for decades, can be invoked against threats unrelated to the original justification, and can outlive the original political coalition that supported it. The 2001 AUMF passed 98–0 in the Senate; by 2026, only a small minority of either party publicly supports its repeal, but a substantial majority would not vote for a similarly broad authorization today. The legal infrastructure has become path-dependent: it is far easier to maintain than to dismantle.

The bipartisan lesson. Every administration since 2001 has used the war-on-terror infrastructure. Some expanded it (Bush, Trump 1, Trump 2); some constrained particular aspects (Obama on enhanced interrogation, Biden on Afghanistan deployment); none dismantled it. The pattern matches the broader argument of this chapter: presidents of both parties accept the inherited authorities of the office and add to them. Critics of any one administration's use of these authorities can point to the predecessor administration's use as precedent.

The judicial lesson. Courts can constrain executive action in important respects without dismantling the underlying program. Hamdi, Hamdan, and Boumediene established meaningful procedural protections — and the system continued to operate. The constraints are real and consequential; they are also limited. In a separated-powers system with a determined executive and an acquiescent Congress, judicial review polices the edges but does not, by itself, reverse the underlying expansion.

A serious citizen who wants to evaluate the post-9/11 trajectory has to weigh both the security rationale (the United States has not suffered a 9/11-scale attack in twenty-five years; the architecture, whatever its costs, has plausibly contributed to that outcome) and the rights costs (indefinite detention, expansive surveillance, targeted killing of U.S. citizens, the normalization of executive war-making far from anything Congress voted on in 2001). Reasonable people, applying the same data, reach different conclusions about the balance. The textbook's job is not to tell you which conclusion is right. The textbook's job is to show you that the question is real, that it spans both parties, and that it is not going away.