(Editor’s note: This essay is part of a Symposium published for the twentieth anniversary of September 11th; co-organized by Just Security and the Reiss Center on Law and Security.)

Two decades after 9/11, the United States remains locked in an accumulated set of intertangled counterterrorism conflicts across the Middle East and Africa: the Forever War. It’s a struggle that President Joe Biden has pledged to end, and his early foreign policy decisions, most notably the U.S. withdrawal from Afghanistan, show that he is seriously committed to that objective. But in other locations across the Middle East and Africa, the United States is grappling with a seeming inertia toward endless military action. And the chaotic withdrawal from Afghanistan and domestic political backlash have raised questions among many foreign policy professionals as to whether we should actually draw down our military operations across the Middle East and Africa. 

After 20 years of war with underwhelming results, ending the Forever War is a worthy goal. Yet ending the Forever War is a complex undertaking that will require disentangling the U.S. role in a set of overlapping conflicts and establishing a new set of legal and policy frameworks designed to constrain the use of force by the United States. It will demand that disengagement from key conflicts is done with care and competence to avoid producing greater instability. And it will require communicating the key efforts to end the conflict in an environment where Biden’s political opponents are eager to use the downfall of Afghanistan, new terrorist threats, or other events that may arise as political cudgels. Having a clear set of guiding principles for ending the Forever War will help the administration to both build public support and motivate the professionals assigned to carry out this difficult process. 

Ultimately, the Biden administration needs to define a new era, one in which militarized responses to irregular threats are a rarity, only conducted after exhausting all other options, and where terrorism is put in proper context alongside other challenges. The goal should be to build a durable framework that greatly constrains the use of force, emphasizes civilian and partner responses, and makes the operations that do take place far smaller and more restrained than those that have predominated across the past two decades. Without clear standards for counterterrorism interventions and effective constraints on the use of force, the United States risks both stumbling into the fray when forbearance would be the wiser course and failing to intervene when action is actually appropriate. Ideally, Congress would be a partner in this goal, stepping up to fulfill its constitutional duty to decide when and where the nation must be at war. But the Biden administration has its own work to do, and despite the difficulty of the Afghanistan withdrawal, it can still diligently pursue a number of steps that could end America’s longest conflict without compromising our security.  

The Current State of Affairs: The persistence of terrorism and irregular warfare

When the Biden team took office, the critiques of the Forever War had become a familiar drumbeat: the United States has launched counterterrorism operations the world over, relying on an expansive interpretation of the 2001 and 2002 Authorizations for the Use of Military Force (AUMF), overstretched military forces, and unmanned drone aircraft to strike myriad terrorist threats that might emerge. In the process, trillions of dollars of taxpayer money and thousands of U.S. lives have been lost, millions of people abroad have been displaced and hundreds of thousands have died (directly or indirectly), and a vast swath from South Asia to the Sahel has been destabilized. Many conflicts of the Forever War are now waged with far less intensity than they once were, but U.S. forces continue to fight against al-Qaeda, ISIS, and their affiliates in at least a half dozen countries. While fewer U.S. forces and financial resources are dedicated to the fight than previously, there are clear and substantial opportunity costs. Simply put, the current form and degree of continued focus on terrorism diverts the attention of senior leaders from the nation’s greatest threats, a dynamic of which our adversaries are all too aware

The chaotic U.S. withdrawal from Afghanistan and the Taliban’s rapid gains injected hesitation into the “end the Forever War” drumbeat and drew scorn from some of the conflict’s biggest advocates, but in many ways, the recent events there have only reinforced why ending the Forever War should remain a top foreign policy priority. The Afghan government’s rapid collapse suggested a fundamental futility in our years-long nation building efforts. The quick rout and surrender of Afghan security forces – after the United States spent more than $83 billion to train and equip them – suggested that even fully-resourced partnership capacity-building efforts may be for naught. And the ability of the Taliban to muster a competent 75,000-person fighting force after two decades of relentless bombing and ground operations suggests how military operations can fall far short of crippling an insurgency. Certainly there are lessons from the Afghanistan campaign that should be preserved for other conflicts, but the major U.S. efforts all failed miserably and in the process, raise profound doubts about our approach to counterterrorism. 

What’s more, while the Forever War is the compelling up-close problem, there is an even bigger challenge lurking: America’s persistent, seemingly unavoidable tendency to get entangled in conflicts short of high-intensity war. 

However much President Biden wants to focus on true existential foreign policy challenges, his docket will almost certainly be filled with a set of irregular conflicts and calls for military action. He must consider how the U.S. government will address concerns like transnational crime, state use of proxies, and calls for humanitarian interventions. Consider just some of the conflicts beyond the war on al-Qaeda and ISIS in which the Obama administration intervened: supporting the multinational campaign to overthrow Libyan president Muammar Qaddafi; deploying military advisors to support the hunt for Ugandan warlord Joseph Kony; sending Navy SEALs to confront pirates off the Horn of Africa; supporting the Saudi-led campaign against the Houthis in Yemen; and providing military support to counter-drug cartel operations in the Western Hemisphere. These are only the military operations President Obama approved. Top advisors also urged large-scale military intervention in Syria to stop Assad’s use of chemical weapons against his population and other war crimes. Others urged him to take action to address mass atrocities and humanitarian crises in Sudan or to get more involved in UN peacekeeping missions. Military and intelligence officials urged him to do more militarily to counter Hezbollah and other Iran-linked groups. 

President Trump was eager to claim anti-war credentials, but he too engaged in a number of military actions: twice launching cruise missiles against the Assad regime in response to its use of chemical weapons; ratcheting up the counter-ISIS campaign in Syria before ramping it down (before ramping aspects of it back up again); escalating operations in Somalia; deploying more special operations forces against terrorist groups; ordering an overt operation to kill Islamic Revolutionary Guard Corps-Quds Force commander Qassem Soleimani alongside an apparent covert operation to kill Iranian commander Abdul Reza Shahlai in Yemen; and a secret cyberattack against Iranian intelligence defense systems. A review of any modern president’s foreign policy record will be replete with instances of irregular warfare and military interventions short of war.

The Pathway Forward: New priorities, persistent questions, and institutional barriers

The good news is that the era of the Forever War as the central organizing principle of U.S. national security is already over. For U.S. foreign policy, COVID-19 and steady rising bipartisan concern over China and Russia in recent years have done what successive administrations were unable to – force the widespread recognition that, while terrorists continue to pose a threat that must be managed, the United States faces far greater challenges. Pandemic disease. Great power competition. Climate change. Cyber threats. Artificial intelligence and other new technologies. The militarization of space. The administration has already sent strong signals that these are its foreign policy priorities. For the first time in nearly a generation, every day is not September 12th. 

But the Biden administration must now confront the uncomfortable reality that actually ending the Forever War raises as many questions as it answers. For one, what does it even mean – the end of long-term ground wars, particularly leaving Afghanistan, or more broadly stepping back from using military force as a default approach to confront terrorism? Should the United States leave some forces in Iraq? Should the United States continue to have some forces in Syria? Should it still be taking targeted strikes in Somalia? In Yemen? Should the U.S. military still conduct partnered operations with local forces, which can effectively share the burden but also pull the United States deeper into conflicts? Should the United States conduct strikes in defense of partner forces when U.S. personnel are not at risk? 

Even if it de-emphasizes counterterrorism, the administration will still need to answer these and related questions. Further, the Biden team must grapple with these questions in the face of institutional forces – civil servants and the military officer corps – that are wary about the risks of ending longstanding operations or chafe at new limitations, and a media and punditry apparatus eager to sharp shoot every misstep and elevate every terrorist threat. And it must consider that its efforts to adjust its approach may face new congressional resistance if the President’s party loses control of one or more chambers of Congress in the midterm elections. 

Purposeful Reform: A set of principles for ending the Forever War

Irregular conflicts – whether related to terrorism or not – do not necessarily demand military responses. Savvy diplomacy, international cooperation, multilateral sanctions, law enforcement cooperation, tailored aid packages, and border security assistance are often more appropriate ways to achieve U.S. objectives, and these should be properly resourced and used as tools of first resort. Yet I don’t believe that ending the Forever War should mean quickly terminating all counterterrorism operations, nor is that a likely outcome. Diplomacy and aid will at times fail or prove insufficient and Biden, or his successors, often operating under immense political pressure, will see use of force as necessary to disrupt an imminent terrorist attack or remove a top terrorist leader. But it’s time to turn the page on the current approach and build a more sustainable strategy, one in which militarized responses are de-emphasized, terrorism is soberly considered alongside other threats, and effective oversight bounds our operations. 

Five key principles, publicly articulated and contextualized around a larger strategy that moves beyond the Forever War, could guide the administration. 

Principle 1 – Contract, don’t expand. If we want to end the Forever War, the first principle should be to actually draw it down and resist temptation to grow what is already a sprawling campaign. This means holding a strong presumption against new counterterrorism missions, theaters, or groups. For example, the Biden team should look warily upon new pushes to deploy advisors to Mozambique and the Democratic Republic of the Congo absent overwhelming evidence that terrorists there threaten the United States in a direct, serious, and immediate way. It also means reducing the size and scope of existing missions in secondary theaters like the Sahel and Somalia and focusing on transitioning responsibility to our local partners as quickly as possible. U.S. military operations should be reserved for only the greatest threats to the United States and where alternative means of addressing the threat are unavailable. This is not a prescription for allowing a situation to get really bad before acting, as the United States did before ISIS seized Mosul in 2014. Rather, it means acting based on a fact-based evaluation of the threat, careful consideration of the risks of inaction, evaluation of alternatives to military action, and humility about what the U.S. military can accomplish. When considering irregular missions unrelated to terrorist threats against the United States, the presumption against using the military should be even higher. 

The act of contracting needs to be comprehensive, and it requires taking a hard look at a global counterterrorism posture that is set up to defend against a threat but at times seems to actively seek one out. Does the United States need so many military task forces focused on counterterrorism? Does it need a persistent presence in Somalia or more than 500 troops and a drone base in the Sahel to combat groups that pose less of a threat to the United States than the core elements of ISIS and al-Qaeda? Does it need special operations forces active in more than 80 countries? The Pentagon is in the midst of a review asking some of these questions, and the new defense leadership should be ruthless in managing these force level and posture issues with the goal of drawing down our counterterrorism operations.

Posture reviews, whether conducted by the Pentagon or civilian agencies, should also carefully consider the U.S. Government’s risk calculus for counterterrorism deployments. On the one hand, the Trump administration relaxed the threshold for deploying U.S. counterterrorism forces, and several military personnel died in the process, including in circumstances where it was not clear that the military objective was worth the risk. At the same time, since at least the terrorist attack on Benghazi in 2012, the U.S. government has often tied its own hands by taking an overly cautious approach to deploying civilians. If the Biden administration prioritizes diplomacy and development in counterterrorism, it should consider how the U.S. military should be postured to support civilians in conflict zones and what additional resources the State Department and U.S. Agency for International Development might need to fulfill this vision. 

Principle 2 – Emphasize, reform, and own partnerships. U.S. efforts to build partnership capacity are at a crossroads and in need of major re-evaluation. As the United States reduces its military presence abroad, it is essential that partners step up. Terrorism and other irregular threats are, by nature, the kind of challenges that require local knowledge and credibility. Local partners must be equally or even more committed to defeating them – or better yet, preventing their emergence – if combined efforts are to succeed. Burden sharing must be increased with European allies and regional partners as well. 

At the same time, the U.S. record on counterterrorism partnerships is deeply disappointing. There have been successes, as with the coalition to defeat ISIS, which brought together more than 80 countries, both traditional allies and regional powers, and local forces all contributing what they could to roll back the threat. But in most places, partnership efforts have been under-resourced, over-militarized, or unsustainable. The United States often provides its partners with high end gear that is greater than what they actually need, which is then only lightly used or they are unable to maintain. Capacity building efforts often focus on tactical commando forces and overlook the broader military or supporting institutions. Police training is carried out by Beltway contractors who hire current and former American cops of uneven quality. Few resources are typically dedicated to building the rule of law. 

On the rare occasions when capacity building is well-resourced, as with Iraq before 2011 and Afghanistan, the United States has often built a replica of its own military, with heavy emphasis on airpower, extensive contractor support, and a reliance on U.S. advisors to support targeting and mission planning. All of this collapses absent strong and persistent U.S. presence.

Further, in the places where U.S. capacity building efforts have failed most miserably – Iraq, Afghanistan, Yemen – mistakes in capacity building were compounded by fundamental political problems within each partner country. Whether that’s corruption, state-sponsored abuses, or the failure to build an inclusive government, factors well beyond the military’s ability to shoot straight have often led to their defeat. In some cases, the United States ineptly managed these political dynamics or even fueled them instead of accepting how these political dynamics would undermine U.S. capacity building efforts and changing course accordingly. In other cases, the politics may have been beyond anything the United States could shape.

What’s needed is nothing short of a top-to-bottom review and reform of capacity-building efforts in security cooperation. The administration must be willing to use political capital – both within the executive branch and with Congress – so that it can shake up the massive, ossified, and broken security cooperation bureaucracy, and establish the governmental capabilities, resources, and programming agility to do capacity building well. The review should also rigorously evaluate the institutional circumstances that contributed to recent security assistance failures and use the lessons here to inform future security sector reform efforts and diplomatic strategies.   

Further, the United States must manage its partnerships carefully, so that proxies and partners established to assume the lead on counterterrorism don’t end up sucking the United States deeper into conflict. It’s a difficult line to draw. Doing it right means getting a handle on the United States’ use of military surrogates and the authorities that enable those relationships, as well as evaluating the theaters, like Somalia and the Sahel, where advisory efforts evolved into extensive U.S. lethal military actions and more U.S. forces in harm’s way.   

When the United States works through partners, it must treat their actions like U.S. actions. Too much of the counterterrorism campaign over the past two decades has involved moral compromises with dodgy partners to counter threats, without accountability. While this may have helped remove some terrorist leaders and slow the growth of some groups, it has also dramatically undermined U.S. credibility and fueled underlying grievances that enable terrorist recruitment. Consider Yemen, where Emirati counterterrorism partners stood up a series of prisons where unjust detention and torture have reportedly been commonplace. Washington simultaneously supported the Saudi-led campaign against the Houthis that has plunged the country into abject misery. In helping preserve this campaign and defending it, the United States compromised its own integrity and moral character in Yemen and other parts of the region. The answer is that the United States needs to demand more of its partners and take accountability when they go wrong. 

Principle 3 – Play a strong defense and use force as a last resort. The United States has built robust defenses over the past two decades, investing hundreds of billions of dollars in law enforcement, intelligence, border security, infrastructure security, and international cooperation against terrorism. Yet, to observe the recent debate around the Afghanistan drawdown, some believe it’s inevitable (only a matter of time) before an Afghanistan-based al-Qaeda tries to strike the United States. Even if that is correct, we must begin to believe, and to understand, that it’s okay to play defense, to rely on our law enforcement professionals, intelligence community, international cooperation, or even armored airliner cockpit doors to prevent terrorist attacks. These capabilities have shown their ability to stop terrorism time and again since 9/11, and we should trust in the defenses and networks we have built to keep threats at bay.

Inevitably, there will be times when the United States must use force to stop threats to the country or to our people that cannot be disrupted in other ways. Yet the Biden administration must push back on what has too often been a rush toward militarism under the belief that if the United States doesn’t aggressively target every threat, its people will be endangered. The U.S. strike, earlier this year, on Iran-backed militias in Syria may be illustrative of the militaristic reflex. The United States is the most powerful nation in the world, with a broad range of foreign policy tools – diplomacy, intelligence cooperation, law enforcement, sanctions, aid – to incentivize or compel actions against terrorist groups and their sponsors. Could these resources have been better marshaled to prevent future attacks on U.S. forces in Iraq? And more broadly, can these tools be the first resort in addressing a range of threats? Absolutely. 

The legal and policy threshold for using force is more complex when the threat is not to the United States, and the Biden administration will need to work through these scenarios as it reviews use of force policies. The administration may consider using force to stop mass atrocities, for example, though questions will inevitably abound as to what constitutes a mass atrocity or the complexities of engaging in a place like Syria where military force could hurt, not help, civilians caught in conflict. Similarly, the United States might take military action to halt a threat against an ally or partner, though consideration would need to be given as to whether that nation could take its own defensive action. 

On those occasions when policymakers decide there is no alternative to the use of force, such operations must be conducted with the utmost care, discrimination, precision, and emphasis on preventing civilian casualties. In most situations, U.S. policy standards should be substantially higher than the baseline legal requirements under the law of armed conflict. The Obama administration put such a framework in place in the president’s second term, with the Presidential Policy Guidance that governed drone strikes outside of hot warzones. That framework codified the need to exhaust all alternatives before using force, limited the scope of strikes, and mandated that strikes could be conducted only if there was “near certainty” that civilians would not be harmed. The Biden administration is reportedly nearing the completion of a review of its use of force policy. It should embrace the Obama framework’s core principles of precision, discrimination, and restraint but go further in ensuring U.S. forces are meeting the guidance and that the guidance contributes to the overall goal of reduced use of force.

Principle 4 – Run a responsible, inclusive, and strategic decision-making process. After the calamitous decision-making of the Trump administration, in which major decisions were made with ad hoc teams of advisors and the National Security Council staff was gutted, a top priority for the new administration appears to be restoring a rigorous policy process. Yet this process should not just snap back to the Obama approach to counterterrorism. The administration needs a new process that begins with a realistic and updated assessment of the specific threat to the United States, risks to U.S. forces, the opportunity costs of using force compared to other national priorities, and the cost to foreign publics. Counterterrorism policy should be fully integrated with regional policy, and counterterrorism tools should be considered alongside humanitarian assistance, development, diplomacy, and other efforts aimed at conflict mitigation. Counterterrorism policy should consider the full range of approaches – such as terrorist financing, law enforcement, homeland security, and countering violent extremism. Further, counterterrorism should take up less time on the docket of top policymakers – and with fewer overseas military operations, this is possible – so that senior leadership can focus more on the existential threats mentioned above.

Rigorous interagency policymaking should not come at the expense of empowering cabinet secretaries, however. In fact, while good interagency process will generally produce well-considered policy, it takes strong department leadership to actually implement. So while all relevant departments and agencies should shape counterterrorism policy, including guidance for the use of force, the Secretary of Defense and his senior civilian staff should be uniquely empowered – and expected – to implement the agreed-upon policy. This means providing effective oversight of military operations and ensuring that they meet the standards recommended by the cabinet and approved by the President. 

Principle 5 – Ensure that operations are lawful and transparent. Finally, any military action that the United States takes, whether against terrorist groups or other irregular challenges, will only be as legitimate as the legal and political foundations on which it rests. This means that all operations should be grounded in a sound legal framework, a commitment to strong congressional oversight, and as much public transparency as possible, so that the nation can understand the fight being carried out in its name. 

At a time when the public and Congress are increasingly wary of foreign wars, waging the fight through an expansive interpretation of executive authorities is neither sustainable nor wise. And following the Trump administration, where the executive branch trounced the legislative branch on a broad range of issues, it is now time to restore balance, particularly when it comes to the most fundamental of authorities, the power to wage war. The United States is now waging most of its counterterrorism operations under a 20-year-old force authorization, enacted quickly in response to the specific attacks of 9/11, at a time when the threat landscape, set of terrorist groups, and American psyche were far different than today. 

It’s time for an authorization that both imposes new limits and adjusts to the new strategic reality. At a minimum, this means Congress should follow through on the current bipartisan push to repeal the dead letter that is the 2002 Iraq war AUMF, and the administration work with Congress to create a new, far more limited version of the 2001 AUMF. These limits should include a time-bound sunset clause, so that Congress must periodically re-examine and re-authorize operations and possibly dissuade the executive branch from the more expansive interpretations of the AUMF that can come without strong congressional oversight. It should include limitations on which enemy forces can be targeted, so that the administration cannot just declare a sprawling set of terrorist groups, associated forces, and successor forces as lawful targets for purposes of the AUMF. And it should provide some parameters — whether that’s a combination of reporting requirements, funding constraints, or restrictions on scale of efforts against enemy forces, or other measures — which work to ensure limited deployments don’t evolve into large-scale conflicts without explicit congressional authorization.

Congressional oversight should also be reinvigorated, with commitments from both the executive and legislative branches to ensure that Congress is concurrently briefed on operations and the basis for conducting them, has the opportunity to rein in operations that go beyond the bounds of congressional authorization, and can develop legislation allowing for greater public transparency. This role has never been more important, given that successive administrations have gutted the War Powers Resolution, stretched the AUMF to its breaking point, and at times treated congressional oversight as an afterthought. To see just how broken congressional oversight currently is, consider the 2019 strike on ISIS leader Abu Bakr al-Baghdadi, in which the White House notified some Republicans, but no Democrats, of the operation prior to it becoming public. Or the strike on Qassem Soleimani, where the Trump administration thumbed its nose at Congress by presenting a swirl of justifications for the action, none of them offered as the definitive explanation and each reportedly disconnected from the true decision-making calculus. Or even the strike this year against Iran-backed elements in Syria, where the administration presented a tenuous Constitution-based rationale for the action and briefed Congress at a staff level only immediately before the attack was conducted. This is not how it’s supposed to work.

As to the public, despite some admirable moves toward transparency over the past decade, much of the counterterrorism fight remains in the shadows. The American public deserves to understand the range of actions conducted in its name. Foreign publics in the countries where the United States conducts operations also need to understand the reason for the actions, the outcomes, and what the United States does to make condolence payments or reparations when things go wrong. Of course, there will always be some sensitive operational information that cannot be revealed publicly, but many of the justifications that have previously been offered to explain why the United States can’t be more transparent – that it couldn’t telegraph to terrorists its targeting standards, that transparency would compromise the special operations forces and intelligence professionals central to our fight, that U.S. partners would never stand for it – have generally proven to be overstated. Within the U.S. federal bureaucracy, institutional interests in secrecy often tend to dominate – citing many of the reasons above – and a concerted push from senior leaders is required to meet broader commitments to transparency. 

A more transparent approach to counterterrorism would begin by ensuring the military has the lead for lethal operations and can transparently discuss the results of specific operations, publicly explaining in a more convincing manner and with admissions where warranted why U.S. assessments of civilian casualties differ from those offered by human rights researchers, and providing comprehensive details on the legal and policy frameworks underpinning U.S. operations (as the Obama administration did in its waning days in office). 

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Of course, principles are one thing. Actual decisions are quite another, as we have seen with the Afghanistan withdrawal. Similar quandaries will emerge in other regions. But in order to shore up support and encourage resilience at the outset, it is essential to articulate now a policy to end the Forever War, a set of principles for doing so, and a sustained public explanation for how adhering to these tenets will help the United States focus on bigger challenges. Absent such an intentional strategy, the administration may well find itself like its recent predecessors – sucked into endless war.