In the aftermath of the attacks of September 11, 2001, George W. Bush worried less about rallying the nation to action against the terrorist threat than about warning an enraged public that the campaign would not end anytime soon. The president referred to the emerging “global war on terror” as a generational struggle—one that would go on well past his own tenure and one that would lack an emotionally satisfying endpoint such as V-J Day or the fall of the Berlin Wall.
There were a number of things that he got wrong in the subsequent conduct of that struggle, but this admonition was precisely right. The war on terror has now spanned nearly two decades and three presidencies with no obvious conclusion in sight. Donald Trump’s speech to the nation on Afghanistan last month reminded Americans of the painfully open-ended nature of the conflict—yet it also showed that the country may have found an appropriate military strategy for waging a struggle that will almost surely outlast a third commander in chief.
Trump’s speech was notable because it represented a marked evolution in his views on Afghanistan and counterterrorism strategy. Even before he emerged as a presidential candidate in 2015, Trump had harshly criticized America’s long wars in Afghanistan and Iraq. As president, his initial instinct was to walk away from Afghanistan. Yet on the recommendation of his advisers, Trump ultimately—and by all accounts, reluctantly—accepted the need for a modest escalation beyond the roughly 11,000 U.S. troops now in Afghanistan, in order to intensify the campaign against extremist groups such as the Taliban, al Qaeda, and ISIS-Khorasan Province. Like Bush and Barack Obama before him, Trump came to accept that the United States cannot simply extricate itself from Afghanistan, lest the country revert to being a safe haven for jihadists seeking to carry out attacks beyond its borders; he also became the third president to endorse an essentially open-ended war on terror.
The reason for this continuity is that America’s predicament in the war on terror remains roughly what it was in the wake of 9/11. For the foreseeable future, a swath of the globe from North Africa to the Middle East to South Asia will remain a fount of instability and ideological extremism. That extremism provides human fodder and an ideological rationale for terror attacks on the United States and its allies. Essentially, terrorist groups are in the business of weaponizing hatred and resentment. They leverage social media and other network tools in the virtual world while they are protected in the real world by safe havens and state sponsors. Safe havens where governments are unable or unwilling to police them and state sponsors that actively collude with extremists unfortunately remain plentiful in those parts of the world.
As the United States learned on 9/11, safe havens and state sponsors enable terrorist groups to scale up well beyond simple acts of violence. They provide an infrastructure for recruiting would-be terrorists, winnowing the recruits to find the most capable, and training the recruits to be more lethal. The United States relearned this painful lesson in 2014, when ISIS created a vast safe haven in the very heart of the Middle East, a quasi-state caliphate. Transformed by this achievement, ISIS became the most powerful terrorist group in modern times, rallying tens of thousands of recruits to its territory and sending them back to launch and inspire attacks throughout the world.
Dealing with this threat requires passive and active defenses. Passive defenses—such as intelligence gathering and homeland security measures—are essential but limited in their results, because a passive approach cedes the tactical and strategic initiative to the enemy and cannot thwart every attack. President Trump, like Bush and Obama before him, has thus concluded that it is necessary also to go on the offensive. This means pressing the terrorists ideologically and politically, to reduce their appeal, and militarily, so they cannot plot and prepare unmolested. The military component is especially vital because it kills the most capable and hardened terrorists and denies them the safe havens that allow them to operate most effectively.
The United States has found all components of a comprehensive counterterrorism strategy challenging, but finding the right balance for the military component has been especially fraught. Since 9/11, U.S. military strategy has oscillated between two radically different approaches. At times America has pursued a heavy-footprint counterinsurgency strategy meant to decisively defeat terrorist groups while enabling the creation of effective government institutions—in other words, nation-building. At other times the United States has taken a very-light-footprint approach, relying on drone strikes and the occasional special operations raids against al Qaeda and its affiliates, along with significant assistance to friendly government forces in countries such as Yemen. In Iraq (2007-12) and Afghanistan (2009-11), Bush and Obama both found that the heavy-footprint approach produced results on the ground but at a political price they found difficult to sustain. Conversely, in Iraq (2012-14), Obama found that the light-footprint strategy proved ineffective in preventing ISIS from overrunning vast swaths of territory.
By the end of the Obama years, the United States had thus shifted toward a medium-footprint strategy in Afghanistan, Iraq, and Syria alike. That strategy entailed deployments of several thousand U.S. troops involved—both unilaterally and in support of friendly partner forces—in aggressive operations meant to roll back safe havens and defeat the most dangerous extremist groups. That strategy, however, eschewed the sort of transformational nation-building attempted in Iraq and Afghanistan in earlier years, even as American officials used economic aid, diplomatic leverage, security assistance, and other tools to empower local partners and encourage marginally better governance. It is this strategy—at least in its military components—that President Trump has now embraced.
To be clear, this third-way strategy does not lack for shortcomings. It requires working patiently with deeply flawed local partners whose interests and values may be quite different from our own. It requires a willingness to support open-ended military commitments that come at a cost in lives and treasure. Not least, this strategy has no near-term “theory of victory.” It aspires to keep the threat from terrorist groups at manageable levels by punishing them militarily and clearing out their safe havens, rather than to remove the threat altogether by conclusively addressing the sociopolitical conditions from which it emanates. A medium-footprint strategy requires accepting that the war on terror will indeed go on without a clear end in sight. And although nation-building is deprioritized in this strategy, it does require working with local partners to enhance their capacity and influence their behavior at the margin.
Yet the medium-footprint strategy also boasts significant advantages. When pursued aggressively—against the Taliban and al Qaeda in the immediate aftermath of 9/11, or against ISIS more recently—it has battered these organizations and kept them off balance. The strategy is not cheap, but neither is the cost prohibitive—annual outlays for the counter-ISIS campaign have averaged around $10 billion, a small fraction of the defense budget. A medium-footprint approach places a heavy operational burden on certain niche capabilities within the military—special operations forces and intelligence, surveillance, and reconnaissance assets—but does not excessively divert the military from demanding threats posed by conventional great powers like Russia and China in the way that larger-footprint operations did in the decade after 9/11. This strategy thus offers a reasonable prospect of dealing with the most dangerous manifestations of the terrorism problem—powerful jihadist organizations that enjoy territorial safe havens—at a manageable price. Compared with a heavy-footprint approach that is too expensive to be sustainable and a light-footprint approach that risks alleviating the pressure on the enemy, a middle-of-the-road strategy doesn’t look half bad.
And this approach easily bests the out-of-the-box option Trump considered: outsourcing the war to private contractors. Relying on private military contractors to do the fighting and training does not eliminate the financial cost of the war. Taxpayers would still be paying someone to fight, and the U.S. government would still be holding the bag if things went awry.
Although some critics have seized on Trump’s speech as simply more of the same militarized approach to the war on terror and called for the United States to begin disengaging from both Afghanistan and that broader conflict, they have rarely answered the hard questions about what would happen if American officials followed their advice. What are the chances that Afghanistan would revert to the terror-breeding conditions of the late 1990s or that Iraq might once again become catastrophically vulnerable to an ISIS-like group, absent persistent U.S. military engagement in those countries? What might the butcher’s bill be in a scenario in which terrorist groups again dominated large swaths of territory and were left to plan and operate in relatively safety? What kind of recruiting and financial bonanza would the terrorists groups reap if the United States finally fulfilled Osama bin Laden’s prophecy and showed itself to be the weaker horse? The answers to such questions are not knowable with any precision. But the price that the United States has paid over the past 20 years when it allowed such conditions to emerge provides little reason to think such concerns can simply be waved away.
The essence of strategy is choosing among imperfect alternatives, and a medium-footprint approach of ongoing military pressure is the best of the bad options when it comes to terrorism. Yet if President Trump thus got the military policy basically right in his Afghanistan speech, he would do well to understand that he got some of the resourcing and a key part of the rhetoric wrong.
First, even the more modest ambition of constructively influencing host-nation governments at the margin is likely to be compromised if the Trump administration proceeds with plans to gut the State Department, foreign aid programs, and other nonmilitary components of American power.
Second, promising victory over the terrorists—as President Trump did—is a recipe for disappointment. For a medium-footprint approach will not bring about anything like a decisive strategic victory—not until the countries of the greater Middle East and South Asia sort out the internal problems that fuel jihadist extremism in the first place. At best, this approach will provide an acceptable if imperfect level of security in an age of enduring terror. That may not sound like much, nearly two decades after the war on terror began. But it may be the best that the United States can hope to achieve at a politically acceptable price.
Hal Brands is Kissinger Professor at the Johns Hopkins University School of Advanced International Studies and senior fellow at the Center for Strategic and Budgetary Assessments. Peter Feaver is a professor of political science and public policy at Duke University.
