Data and Definitions

This section provides a brief summary of the method and data sources used in this paper and their limitations as well as definitions of key terms used throughout the paper, including preventive war logic.

The primary set of sources for evaluating decision making in the counter-ISIS war are 28 speeches, statements, remarks, and War Powers Resolution letters made or written by President Obama that addressed ISIS and the counter-ISIS war archived on the White House website (see Appendix). These sources were drawn from a review of all statements available on the archived Obama White House website from January 2014 through the end of September 2014.

This report distinguishes between these 28 statements (hereinafter referred to as official presidential statements) and remarks the president made in media interviews but not recorded on the White House website. The 28 statements were supplemented with other speeches, statements, news reports, memoirs, congressional testimony, and a small number of interviews.

Relying primarily upon Obama’s official public statements has limitations. The speeches represent the final, public justification presented by the administration and may not reflect the actual timing of a decision or more private justifications. The supplemental sources used in this paper provide a limited corrective.

The decision to limit the time period examined in detail to January 2014 through the end of September 2014 raises the possibility that the justifications for the war changed substantially after September 2014. Future research should expand the period under examination, however this report focuses on when the war was initiated as a particularly important starting point for analysis.

In assessing the threat posed by ISIS to the United States, this report relies on thousands of pages of court documents, New America’s Terrorism in America database, databases maintained by New America and others on foreign fighters, and government threat assessments. These sources were supplemented by interviews with experts and policymakers with insight into the threat ISIS posed.

Any historical threat assessment is at risk of hindsight bias. This challenge is compounded by the difficulty of counterfactual analysis involving preventive war. As former New America/ASU Future of War Fellow Scott Silverstone writes in his book on preventive war, preventive action “wipes away knowledge of what the future might have held, thus wiping away our ability to judge whether it was actually necessary to avoid an even worse course of events than what preventive attack itself produces.”¹ This report makes special effort to clarify what threat dynamics were known to policymakers at the time and to note the potential for alternative outcomes.

Throughout this report, reference is made to preventive war logic. This report defines preventive war logic as a reasoning, justification, or motivation for war based on the belief that war now is preferable to other options as a way of preventing a future conflict in which a rival actor would pose a greater threat due to a growth in its capabilities.

The fear of growing capabilities is central to preventive war logic. There may be other rationales that fall under the category of “better now than later” logic, but only those that seek intervention now to forestall facing a rival with greater capability later are preventive.²

Preventive logic has too often been confused with preemptive logic.³ Preventive logic is distinguished from preemptive logic based on the immediacy of the perceived threat as well as the character of the reasoning. Preemption is generally understood to involve a response to an imminent threat that will manifest regardless of whether the threatened party acts first but in which acting first might provide an edge in the coming conflict. In contrast, preventive war is generally understood as the use of war to shape circumstances to avoid a future threat that is not yet imminent and thus may not happen in the absence of the use of force.⁴ This is not merely a distinction of timeliness. Preemption is not aimed at preventing a growth in capability, but instead at avoiding the consequences of military attack or achieving tactical benefits like surprise by striking first.⁵

Preventive war is generally understood as the use of war to shape circumstances to avoid a future threat that is not yet imminent and thus may not happen in the absence of the use of force.

In referring to “preventive war logic” rather than “preventive war” this report foregrounds the decision-making process and the role of preventive justifications for military action rather than the categorization of the war’s primary purpose. As the scholar Jack S. Levy argues, “most wars have multiple causes, and to identify a war as ‘a preventive war’ privileges one cause over others … Preventive logic can also influence the timing of a war sought for other reasons, and it would be misleading to characterize the war as ‘a preventive war.’”⁶

Preventive war logic is only one of many rationales for war that were cited with regards to the counter-ISIS campaign. This subsection describes four other motivating rationales of relevance to this report. It is important to note that these other rationales can also be framed in preventive terms. Where this report refers to preventive war logic, unless otherwise noted, it refers to preventive war logic in the context of the security of the American homeland.

Extraterritorial Protection of Americans

This report defines the rationale of extraterritorial protection of Americans as justifications or motivations for the use of military force aimed at protecting specific Americans abroad from direct threats to their lives. Such a justification for war has a long history with regards to the American use of military force.⁷ This rationale is distinguished from regional security rationales (described below) by its focus on threats to specific Americans rather than on threats to regional structures that may be beneficial for American interests.

Humanitarian War

Humanitarian war rationales are defined in this report as justifications or motivations for the use of military force to protect non-American civilians from unlawful killing, war crimes, and atrocities. This rationale is distinguished from extraterritorial protection of U.S. persons by its focus on non-U.S. persons. It is distinguished from regional security rationales by the reference point of what is being protected—civilians from illegal threats as opposed to societies as a whole or particular U.S. interests. As with the logic of extraterritorial protection of Americans, the United States has a history of intervention citing humanitarian war rationales.⁸ Of particular relevance, the use of the military to prevent genocide is a widely supported rationale for the use of American military power in much of the American foreign policy community, although such support has declined in the wake of the 2003 Iraq invasion and remains controversial internationally.⁹

Regional Security

Regional security rationales are defined in this report as motivations or justifications for the use of military force to protect the security of populations writ large, trade, or preferred societal arrangements and conditions in territories that are not part of the U.S. homeland.¹⁰ It is important to note that regional security rationales can still address threats to Americans. Many Americans travel—or even have familial ties—to Europe and parts of the Middle East that ISIS threatened. For example, Americans died in ISIS's 2015 attacks in Paris and Brussels, and ISIS murdered Americans taken hostage in Syria.¹¹

Homeland Self-Defense

This report defines homeland self-defense rationales as motivations or justifications for military force in order to diminish or eliminate an existing direct threat to people within the territorial United States or to the territorial integrity of the United States.

Protected by two oceans and the strongest military in the world, the United States has been extremely fortunate in largely avoiding direct threats to the homeland in modern times. One has to go back to World War II to find an American war arguably premised on responding to a direct threat to the territorial integrity of the United States.¹² However, the United States has at times waged wars against terrorist groups with known, demonstrated capabilities to directly attack the United States.¹³