Instead, the Libyan war bears similarities in motive to earlier postwar interventions. Haiti, Somalia, Afghanistan, Iraq, and even the former Yugoslavia did not raise the prospect of nation-state war of the kind that characterized the nineteenth and twentieth centuries. Aside from Iraq in 1991, which posed a threat to Kuwait, Saudi Arabia, and perhaps Israel, these countries did not menace their neighbors with aggression. Instead, they threatened the international system because of the internal conduct of their regimes.
Quite a few legal commentators argued, in the wake of the Kosovo intervention, that international law does not authorize resorting to war, even for humanitarian purposes.42 The U.N. Charter allows military force in “self-defense,” which can include aiding another state under attack.43 But, according to many commentators, the Charter does not authorize outside states to deploy force to protect a threatened minority population against its own government. That reading of international law will be less compelling, however, if intervention becomes less costly, both for the intervening power and the targeted state. Drones might identify and disable the military units, either on the side of the government or rebels, in a civil war. They could destroy transportation used to carry prisoners and their detention camps too. They could compile detailed views of relevant sites, which might then come under scrutiny by international inspections. Cyber attacks might be used to disable broadcasting and social media, such as the radio broadcasts that incited the massacres in Rwanda.
New technology will make it easier to intervene to stop humanitarian disasters, but these options will not always render intervention effective or wise. What is stopped at one point may resume at a later time. What does not happen may not have happened. Outside states cannot intervene every time civilians are at risk of terrible violence. Premature or ill-judged intervention may even trigger hostile responses from local populations or goad outside powers to intervene. Technology won’t supplant the need for judgment, but it will make it much harder to claim an inability to use force.
Technology will also erode rules that seek to limit the focus of interventions. In the 1990s, some critics questioned why Britain or the United States had not bombed rail lines leading to Nazi death camps during the Second World War. A considerable debate ensued on whether such action was feasible and whether it would actually have saved many lives.44 Yet, as a contemporary European scholar has noted, AP I would now prohibit such action, because interfering with the operations of a concentration camp would not offer a “definite military advantage” to the attacker (as required by AP I’s definition of legitimate “military objectives”).45 When there is a chance to save lives by ignoring the AP I rules, responsible governments will find it easy to bend those rules.
A cramped view of the right of nations to intervene for humanitarian purposes will likely fail if new weapon systems prove their value in preventing catastrophes. Their primary value may not be physically disabling the instruments of mass persecution but in making clear that leading nations may intervene to prevent such horrors. Using force can be as important for its political or psychological impact as its immediate physical effects. If new weapons can act as a warning or a marker, nations will not limit their use to extreme humanitarian crises.
Terrorism
Terrorist groups unconnected with any one nation-state, but nurtured in the ungoverned territories of failed states, present yet another security threat. The defining characteristic of terrorists is their lack of allegiance to any nation. The September 11, 2001 hijackers, for example, launched their attacks as part of the al-Qaeda network of Islamic radicals. Several were from Saudi Arabia, one of the U.S.’s oldest allies in the Middle East. Though they operated from a safe haven in Afghanistan, the hijackers had no defined territory, cities, or people to defend. They received funds from private and religious charities and drew manpower from a pool of disaffected, alienated, or unemployed young men bitter over the Arab world’s decline.
Instead of common ethnic or local origins, al-Qaeda members are unified by an Islamist-inspired desire to engineer fundamental political and social change in the Middle East. They seethe at the rise of the Christian West, the collapse of the historic caliphate, the presence of American troops in the region, and the corruption of Arab regimes. To them, the United States is the primary cause of the conflicts and reversals suffered by the Islamic world. They believe that attacks on the U.S. will convince it to withdraw from the Middle East and cease support of existing Arab governments. Victory for al-Qaeda does not involve defeating U.S. military forces and negotiating a peace settlement, but demoralizing an enemy’s society and coercing it to follow its political goals.
Terrorism depends on unpredictable, sporadic, and quick strikes on civilians using unconventional methods. The 9/11 hijackers wore no uniforms, did not operate in regular units, nor did they carry their arms openly, as required by the customary rules of warfare. Terrorist networks organize their personnel, materials, and leadership into covert cells, which can operate overseas or within the United States itself. While these features may have been present with other groups for many decades, new channels of global commerce and transportation have given terrorists more effective means to organize, finance, and move operatives into positions for attack. These new technologies allow terrorist groups to strike from half the world away with a destructive power that only nations once could exert. Few nations could have duplicated the September 11, 2001 leveling of the World Trade Center in New York City and the attack on the Pentagon using conventional weapons alone.
ISIS’s rise has expanded the terrorist threat beyond the high-casualty, spectacular attacks that were al-Qaeda’s hallmark. ISIS enjoys some of the attributes of a state. It seized territory in Syria and Iraq in 2014, including the major city of Mosul. It controls population, at one time reaching to several million people, and considerable resources within that territory.46 It performs some government functions, such as a justice system that enforces its interpretation of Sharia law (however barbaric), taxation, and welfare services. On the other hand, it does not conduct diplomatic relations, nor does it seem capable or interested in upholding its responsibilities under international law. One of those important duties is to prevent its territory from being used as a base for attacks on its neighbors. If anything, ISIS exists to spread a fundamentalist Islamic revolution that calls for the replacement of existing Arab regimes with a universal caliphate. It uses its territory as a training camp and staging ground for fighters who will remain in the region or travel to western nations to launch terrorist attacks covertly.
Terrorism places further demands on self-defense. Terrorist groups do not deploy large military forces. American intelligence cannot effectively use satellite reconnaissance to detect the deployment of terrorist units days or weeks in advance. Terrorists do not launch cross-border attacks with regular armed units to seize territory, rather, they seek to covertly infiltrate a country by blending into domestic society. Their goal is to launch surprise attacks primarily on civilian targets. A temporal imminence test loses its value if a nation cannot detect the enemy’s preparations in anticipation for war. By the time the nation detects an attack, it may well be too late because the attack will already have occurred. As WMD technology becomes cheaper and more available, the difficulties posed by terrorism will only increase. Groups such as al-Qaeda, Hezbollah, and Hamas have the financial resources to acquire chemical, biological, and perhaps even nuclear weapons capable of killing tens of thousands of civilians indiscriminately. Imminence as a limiting rule on the use of force suffers because non-state enemies can launch attacks with greater speed, surprise, and destructiveness than ever before.
In order to fight terrorism effectively, nations will have to use force well before an attack becomes imminent. They will have to act when a terrorist leader or a collection of fighters becomes known to intelligence agencies, even though they may be weeks or months away from executing a possible plot. At the same time, because the odds of an attack are lower, it would be reasonable to resort only to less harmful methods of coercion. If a terrorist attack were imminent, a government