The five essays in this Agora, written by Jack Goldsmith and myself, Ashley Deeks, Ryan Goodman, Rebecca Ingber, and Michael Ramsey, consider the legal legacy of the Obama administration concerning the use of military force, with respect to both domestic law and international law. Prominent developments during the Obama administration relating to war powers include the administration's defense in habeas litigation of its authority to detain members of Al Qaeda and associated groups in military custody; its increased use of targeted killing outside of active combat areas, in part through frequent missile attacks carried out by drones; its use of military force in 2011 against the regime of Libyan leader Muammar Qaddafi, pursuant to a United Nations Security Council resolution; its deliberations in 2013 about the use of military force against Syria in response to the use of chemical weapons by the regime of Syrian President Bashar al-Assad; and its initiation of a long-term conflict against the Islamic State in 2014. This Agora touches on these and other developments and offers a range of perspectives.

In the fifteen years since the Authorization for Use of Military Force (AUMF) was enacted on September 18, 2001, the Taliban has been removed from power but not eliminated; Osama Bin Laden has been killed and the senior leaders of Al Qaeda as of 9/11 have been captured, killed, or driven underground, although Al Qaeda remains a threat; numerous Al Qaeda affiliates have sprung up around the globe, most notably in Iraq, Yemen, Syria, and Somalia; and most ominously, the Islamic State has arisen from the ashes of Al Qaeda in Iraq to become what the Director of National Intelligence has described as “the preeminent terrorist threat” against the United States “because of its self-described caliphate in Syria and Iraq, its branches and emerging branches in other countries, and its increasing ability to direct and inspire attacks against a wide range of targets around the world.”

Despite massive changes in the geographical scope of the conflict that began on 9/11, the strategy and tactics employed, and the identity of the enemy, the AUMF remains the principal legal foundation under U.S. domestic law for the president to use force against and detain members of terrorist organizations. The AUMF is already the longest operative congressional authorization of military force in U.S. history, and, as of fall 2016, there was no immediate prospect that Congress would move to repeal or update it. With the continued vibrancy of Al Qaeda, its associates, and the Taliban, and with the 2014 presidential extension of the AUMF to cover military operations against the Islamic State, the AUMF is likely to be the primary legal basis for American uses of force for the foreseeable future.

When President Barack Obama came into office in 2009 in the midst of serious, ongoing terrorist threats to the United States, he confronted important choices about how to approach the bodies of international law that regulate the resort to force and the conduct of armed conflict. By many accounts, the Bush administration had taken a maximalist approach to those bodies of international law, staking out broad substantive claims about what international law permitted in resorting to force and in detaining and treating members of Al Qaeda, and asserting those claims publicly and frequently.

The Obama administration has repeatedly taken a notably different tack, employing an approach that we might characterize as “executive minimalism.” That is, the Obama administration has signaled to other states its interest in self-constraint by making fewer bold substantive and rhetorical claims related to the jus ad bellum and jus in bello. It has pursued this objective partly by establishing various policies that authorize a narrower scope of action than what some believe international law permits. In particular contexts, it has also been more hesitant as a rhetorical matter to assert precise legal claims about what international law allows or where international law's limits lie. Accordingly, the Obama administration has sometimes taken action in the face of two (or more) possible legal theories without articulating its specific rationale.

Since September 11, 2001, legal experts have focused significant attention on the lethal targeting of individuals by both the George W. Bush and Obama administrations. An equally significant legacy of the post-9/11 administrations, however, may be the decisions to target specific kinds of objects. Those decisions greatly affect the success of U.S. efforts to win ongoing conflicts, such as the conflict with the Islamic State of Iraq and the Levant (ISIL). These decisions may also become precedents for military attacks that states consider lawful, whether carried out by cyber or kinetic means, in future armed conflicts.

To achieve the goal of destroying ISIL, President Obama embraced what many in the international law community long regarded as off-limits: targeting war-sustaining capabilities, such as the economic infrastructure used to generate revenue for an enemy's armed forces. Although the weight of scholarly opinion has for years maintained that such objects are not legitimate military targets, the existing literature on this topic is highly deficient. Academic discussion has yet to grapple with some of the strongest and clearest evidence in support of the U.S. view on the legality of such targeting decisions. Indeed, intellectual resources may be better spent not on the question of whether such objects are legitimate military targets under the law of armed conflict, but on second-order questions, such as how to apply proportionality analysis and how to identify limiting principles to guard against unintentional slippery slopes. In this article, I discuss the legal pedigree for war-sustaining targeting. I then turn to identify some of the most significant second-order questions and how we might begin to address them.

As we contemplate the incoming presidential administration, we stare ahead into uncharted space. It may seem as though recent history leaves us unprepared for what lies ahead. What can a discussion of the Obama war powers legacy, and the transition from the Bush to Obama administration, tell us about a transition from Barack Obama to the next president, and beyond?

Yet there are lessons here. Noone can predict precisely how the president-elect and the team that is installed will confront the rule of law or grapple with the bureaucratic norms that I discuss in this paper. But systemic forces exist inside the executive branch that influence presidential decision-making in each modern administration and, barring a total reimagining of the executive branch, will operate on administrations to come. These internal forces include mechanisms and norms that fall within two broad categories: (1) those that favor continuity and hinder presidents from effecting change, and (2) those that incrementally help ratchet up claims to executive power.

In 2007, presidential candidate Barack Obama argued that the U.S. president did not have independent constitutional authority to use military force except in response to an actual or imminent attack on the United States. Since 2008, President Obama has directed the use of U.S. military force in at least seven countries (Iraq, Syria, Libya, Yemen, Afghanistan, Pakistan, and Somalia). Critics find inconsistency in these positions, contending that the Obama presidency will be remembered for expansion of the presidency's war powers. But when the administration's record is closely examined, these claims seem overstated. At least with regard to war initiation, the Obama presidency need not be regarded as materially enhancing the president's constitutional powers.

This assessment begins by establishing two baselines. First, most war powers scholars agree that under the Constitution's original meaning, Congress’ power to “declare War” required the president to seek congressional approval prior to initiating war. This constitutional command had substantial grey areas, including responses to threats and attacks, relations with non-state actors, and low-level hostilities. Nonetheless, the basic proposition stated by candidate Obama appears well founded both in the Constitution's text itself and in early postratification practice. Second, in the modern (post-Vietnam War) era, most scholars agree that the practice has changed somewhat, with presidents asserting an expanded independent authority over uses of military force. This essay agrees with that description, although it contends that the change in actual practice is less dramatic than commentary sometimes claims.

The International Law Commission held its sixty-eighth session in Geneva from May 2 to June 10, and from July 4 to August 12, 2016, under the chairmanship of Pedro Comissário Afonso (Mozambique). Notably, the Commission completedonsecond reading a full set of eighteen draft articles with commentaries on the protection of persons in the event of disasters and recommended to the United Nations General Assembly that it elaborate a convention based on the draft articles.

Additionally, the Commission adopted on first reading a complete set of draft conclusions, with commentaries, for two topics: identification of customary international law; and subsequent agreements and subsequent practice in relation to the interpretation of treaties. As such, both topics might be completed by the Commission on second reading in 2018.

Progress was also made in developing draft articles on crimes against humanity; draft guidelines on protection of the atmosphere; draft conclusions on jus cogens; and draft principles on protection of the environment in relation to armed conflicts. The Commission commenced a debate on a proposed draft article on “limitations and exceptions” to the immunity of state officials from foreign criminal jurisdiction, but, due to insufficient time, the debate will continue in 2017. Furthermore, an additional proposed guideline on the provisional application of treaties was sent to the drafting committee. The Commission decided to add two new topics to its long-term work program: the settlement of international disputes to which international organizations are parties; and succession of states in respect of state responsibility.