The withdrawal of US troops from Afghanistan offers the opportunity for a recalibration in the use of force abroad in what is America’s truly longest war—the global war on terror. The Biden administration is poised to increase its reliance on “over-the-horizon” operations—a euphuism for drone strikes and special operations force raids—to ensure that Afghanistan does not, once again, become a safe haven for transnational terrorism. In a speech marking the end of the war in Afghanistan, President Joseph Biden portrayed limited force as a moral alternative to the forever wars, a strategic choice to address terrorist threats in a disordered and divided world. But this framing forecloses serious debate on whether the United States should be resorting to force at all and to what ends. If we are to truly turn the page on the 9/11 era, it is imperative to interrogate the antecedents, assumptions, and principles underlying the over-the-horizon approach. Doing so raises concerns about whether a shift to limited force can really end the forever war, but also points to moral insights that may better guide the “targeted, precise strategy” President Biden has promised.

The Arc of Limited Force

In many ways, the strategic shift in Afghanistan is more of a course correction than a break from the past. Some might say a rebranding. Successive US presidents of both parties have turned to limited force as a less risky, less costly option—in terms of blood, treasure, and public opinion—than conventional warfare. Along the way, policymakers have routinized, institutionalized, and legitimized limited force. Even the terminology has been sanitized to make limited force morally palatable; the United States used to worry about assassinations, but as the lexicon has shifted over time—from “rolling attacks” to “lethal, targeted action” and now to “over-the-horizon” strikes—that worry has receded.

In Afghanistan, the use of limited force predated the 2001 invasion. After the US embassy bombings in Kenya and Tanzania in 1998, the Clinton administration considered multiple policy options to respond to the perpetrators—Osama Bin Laden and al-Qaeda—who were operating in then Taliban-controlled Afghanistan. A ground war was ruled out due to the expected costs and perceived lack of support from the international community, while special operations force raids were considered too dangerous. Instead, the Clinton administration relied on a combination of limited force and transnational law enforcement, launching cruise missile strikes against al-Qaeda targets as part of a plan to conduct “rolling attacks” where the need and opportunity arose. As a legal matter, the mainstream view at the time was that these strikes were a violation of international law. Strategically, the policy did not keep al-Qaeda at bay.

The 9/11 attacks propelled the United States into all-out war in Afghanistan and later Iraq, even as the Bush administration embarked on a parallel, covert drone war that continues today. The hasty passage of the 2001 Authorization for Use of Military Force (AUMF) provided a legal blank check for these abuses, allowing President Bush—and subsequent administrations—to target al-Qaeda, the Taliban, and “associated forces.” Increasingly permissive legal interpretations of this authority, including the claim that it covered groups that did not even exist at the time when it was written, gave the president controversial power to target those deemed a threat to national security even outside official war zones. This mandate, as well as the subsequent 2002 AUMF, which authorized the invasion of Iraq, widened the aperture of the conflict and provided a legal justification for the ever-expanding use of force abroad.

The Bush years exposed the risks and challenges of relying on limited force in an amorphous and poorly defined conflict. In the absence of uniforms and battlefields, distinguishing legitimate from illegitimate targets required near omniscience, particularly as farmers became insurgents and vice versa, transitioning seamlessly between combatant and civilian status. The US approach to this problem was to target unidentified individuals in “signature strikes” based on suspicious patterns of activity, while counting all killed military-age males in the strike zone as “combatants.”

These challenges persisted during the Obama administration, even as it sought to impose strict restrictions on direct action. President Barack Obama increased transparency on the drone program, required “near certainty” that civilians would not be harmed, and expressed a preference for relying on law enforcement—capture, rather than kill, operations—to mitigate terrorist threats. But thorny legal issues surrounding detention at Guantánamo Bay militated against capture, and the war paradigm remained in place as the drone program expanded. Ultimately, President Obama conducted ten times more drone strikes than the Bush administration, with an average of one strike every 5.4 days, although this tempo slowed dramatically in his second term. The restrictions on direct action, meanwhile, were enshrined in policy guidance rather than law, with the 2001 and 2002 AUMFs still firmly in place.

The Trump administration followed suit, albeit with fewer safeguards and transparency measures. President Donald Trump even introduced targeted drone strikes into interstate relations with the January 2020 targeted killing of Iranian Qods Force commander Qassem Soleimani in Iraq. This strike led the United States to the brink of war with Iran, indirectly resulting in the deaths of 176 civilians when Tehran mistakenly shot down an airplane in the period of heightened tensions that ensued. The Trump administration claimed the strike was legal under the 2002 AUMF, notwithstanding the fact that Soleimani—as an Iranian official—did not meet the criterion of a “continuing threat posed by Iraq.” Rather than ending the forever wars, President Trump demonstrated a broader willingness to ignore fundamental constraints on the use of force.

The upshot is this: President Biden has promised to end the forever wars, while pledging to continue over-the-horizon operations. Those claims are in clear tension. As the Biden administration contemplates the guidelines for over-the-horizon force—the long-awaited presidential policy memorandum guidance—it is time to revisit past assumptions about limited force, charting a new path of restraint that bends toward the ideals of law enforcement.

Not Quite War, but Not Law Enforcement Either

With the failure to achieve military victory in Afghanistan, the law enforcement paradigm has once more come to the fore. One of the purported main lessons from Afghanistan, as Mary Kaldor observes, is that terrorism should be addressed solely through policing and intelligence work, rather than war.

Yet transitioning to the law enforcement paradigm may prove difficult. In spaces of contested and fragmented order, law enforcement is extremely challenging, if not impossible, to carry out. In parts of Somalia, for example, the state has only tenuous control over its territory, where al-Shabaab remains resilient. In Yemen, al-Qaeda in the Arabian Peninsula has taken advantage of the chaos ensuing from the civil war to improve its ability to launch attacks. In cases such as these, capture, arrest, and other nonlethal options often appear foreclosed. The same, one worries, will come to be true in Taliban-controlled Afghanistan. The Islamic State in Afghanistan trains and hides in remote mountain regions along the Pakistan-Afghanistan border. Is it only a matter of time until the group becomes a threat to the US homeland, like al-Qaeda of generations past?

Despite emphasis on cooperation with local partners, the Biden administration has signaled it will continue to strike targets that it deems pose a threat to national security. But without boots on the ground drone operators will rely on less reliable intelligence, resulting in greater epistemic uncertainty concerning the imminence of threats and identity of targets. The recent US drone strike that killed ten innocent civilians—including seven children—after mistakenly identifying an Afghan aid worker as an Islamic State facilitator, attests to this risk.

While all casualties in war are tragic, there is something particularly wrongful about these deaths despite cavalier claims, initially, that it was a “righteous strike.” It’s not just that the casualties occurred in a civilian, densely populated area—which, even in war, should have militated against the strike. The strike and the fallout raise questions as to whether the Biden administration is committed to tightening the Trump administration’s “reasonable certainty” metric, which was a watered down version of the Obama administration’s ethical guidelines, to guard against civilian harm.

If this strike was an anomaly, a misguided strike undertaken because of the real fear that US troops were at risk in a war zone that was winding down, then maybe we don’t need to worry too much about the over-the-horizon strategy. Mistakes, unfortunately, happen in the fog of war. But drone strikes ought to be immune to the fog of war. If Biden’s over-the-horizon foreign policy means taking strikes whenever broader US interests are at stake, then the end of the war in Afghanistan would merely be a shift to war by another name.

A future in which the United States maintains a steady pace of over-the-horizon operations might not technically be war, but to pursue this strategy would cause familiar problems. For starters, it would arguably represent the aerial domination of another people outside a declared war zone. Holding civilian populations perpetually at risk in order to guarantee our own safety, however, is morally problematic because it violates the principles guiding the just use of limited force. Moreover, the lure of previous iterations of the over-the-horizon paradigm turned out to be chimera. The idea was that the use of limited force would lead to a “tipping point” where terrorist groups were largely defeated and local law enforcement would suffice to deal with threats to international peace and security. Drone strikes would thus no longer be needed. However, despite claims from Obama that al-Qaeda was “on the path to defeat,” the tipping point never really came. The United States has continued to wage war on terror. Under President Trump, drone strikes surged, but with less transparency. Rather than a shift back toward law enforcement, the war paradigm has persisted.

The challenge that the Biden administration now faces is this: Will such a trend continue? Or will there be a committed shift away from the war paradigm?

The Way Ahead

As the Biden administration revisits its counterterrorism strategy for Afghanistan, it must learn from these past mistakes. In particular, any over-the-horizon strategy that claims to end the forever wars should address the following concerns.

First, policymakers must set clear strategic objectives for counterterrorism operations and articulate how over-the-horizon operations advance them. What does the administration seek to accomplish through the use of limited force? In the past, the use of limited force amounted to years of sustained counterterrorism pressure to disrupt threats to the homeland. Continuing with this approach will not end the forever wars. Recent research on the ethics of limited force suggests that limited force aims to deter, compel, or contain threats, while taking measures to restore the conditions needed for law enforcement. Limited force, in other words, must be deployed in concert with diplomacy and other policy tools in order to advance strategic, not merely tactical, ends. A recent speech by the assistant to the president for homeland security, Dr. Liz Sherwood-Randall, expressed something along this line, but we’ve heard such overtures before. To avoid past precedents, drone strikes need to become a reluctant last, as opposed to first, resort of over-the-horizon counterterrorism policy.

Second, even when limited force is used strategically, there must be stricter procedures in place surrounding target selection, identification, and verification. The worry is that the Biden administration’s over-the-horizon counterterrorism strategy will amount to more of the same old thing. However, the just war standards that used to govern actions in Afghanistan are no longer applicable because the war has ended. More restrictive criteria are needed.

While it may be impossible to have clean over-the-horizon strikes, steps can be taken to attenuate the risks. Individuals should not be targeted solely because they are (alleged) members of a particular group; there must be additional evidence that they qua individuals pose an unjust and imminent threat. In other words, individuals should be targeted only if they pose a threat to life, the threat is temporally imminent, and the use of force is necessary and proportionate. These instances, if they exist, will be rare. The amorphous views of imminence characterizing previous drone policies needs to be abandoned in favor of alternative policy tools that can mitigate terrorist threats in the medium to long term.

This means the United States must end the practice of status-based targeting and pattern-of-activity strikes—practices that led drone operators to target an aid worker who was carrying water jugs, not bombs near an alleged terrorist safe house. Instead, policymakers should be able to identify who it is targeting at all times and possess evidence (such as intercepts) that indicate that the target has both the intent and capability to carry out planned attacks. The United States defended this mistake as tragic but not illegal under the laws of war, but the ethics of limited force should be held to stricter standards when it comes to civilian casualties.

The United States has ended the war in Afghanistan and now must shift away from reliance on international humanitarian law, which is too permissive when it comes to civilian casualties, particularly in urban areas. Instead, the Biden administration must shift toward compliance with international human rights law, where lethal action is permitted only to stop a temporally imminent threat to life. This is a very narrow view of necessity compared to just war standards. The guidance should also adopt a narrower view of proportionality, where the benefits and harms arising from the use of force are measured directly in terms of human life rather than military advantage or, worse, nebulous national security interests. Reverting to the Obama-era “near certainty” requirement that civilians will not be harmed is a starting point, though holding to this standard will be difficult without on-the-ground information.

Finally, the Biden administration must not impose over-the-horizon operations on the Afghan people against their will. This implies that the United States must seek Taliban consent for eventual drone strikes in the country, even when it is unpalatable to do so. Regardless of how the Taliban came to power, the group is now the de facto representative of the Afghan people. If the Taliban tries to sabotage US counterterrorism operations, then it must be held accountable. But a worse outcome would be to operate without permission on Afghan soil. For law enforcement to have any chance at being successful, cooperation with regional partners is essential.

Even when over-the-horizon force meets these standards, the onus is on policymakers to explain how such operations make Americans, the Afghan people, and the world safer. The ease of killing remotely has made limited force a politically expedient option short of war, foreclosing serious debate on less harmful means of defeating threats. At the same time, overreliance on drone strikes to preempt terrorist threats has stretched the concepts of necessity and imminence to the breaking point, lowering the threshold for the use of force. The Biden administration has an opportunity to correct these mistakes and end not just two decades of forever war, but also the mindset that has allowed unlimited, limited force to replace it.

Daniel Brunstetter is an associate professor of political science at the University of California, Irvine. The author of dozens of publications on the ethics of war, his most recent book with Oxford University Press (2021) is Just and Unjust Uses of Limited Force.

The views expressed are those of the author and do not reflect the official position of the United States Military Academy, Department of the Army, or Department of Defense.

Image credit: Airman 1st Class Christian Clausen, US Air Force