In October, the U.S. intervention in Afghanistan will turn 17. The human and material costs of what has become the United States’ longest-ever war are colossal. More than 2,000 U.S. military personnel have been killed and over 20,000 have been injured. The UN estimates that nearly 20,000 Afghan civilians have been killed and another 50,000 injured since 2009 alone. The United States has spent some $877 billion on the war. The Trump administration’s recent initiative to seek direct peace talks with the Taliban—a first since the start of the war in 2001—highlights that Washington is actively looking for new ways to wind down its involvement in the conflict. But why has the U.S. intervention lasted so long in the first place?

Part of the answer is that Afghanistan’s toxic mix of “state collapse, civil conflict, ethnic disintegration and multisided intervention has locked it in a self-perpetuating cycle that may be simply beyond outside resolution,” as Max Fisher and Amanda Taub summarized in a New York Times post. But their diagnosis does not speak to a critical dimension of the conflict: namely, how the relative indifference of the U.S. public has allowed the war to drag on.

In theory, leaders in a democracy have incentives to heed public preferences or risk being voted out of office, which means that public opposition to a war makes its continuation untenable. Yet when it comes to Afghanistan, the U.S. public has favored the status quo at best and expressed deep ambivalence at worst. In polls taken a year ago, only 23 percent of Americans believed the United States was winning the war in Afghanistan, and a plurality (37 percent) supported a troop drawdown. At the same time, however, 44 percent wanted to either keep troop levels about the same or increase them, while 19 percent did not have an opinion. Another poll showed that 71 percent of respondents agreed that “full withdrawal of U.S. troops from Afghanistan would leave a vacuum that would allow terrorist groups like ISIS to expand.” Americans are not necessarily enthusiastic about sending more troops to Afghanistan, but they certainly are not clamoring for withdrawal.

Contrast this with the vocal opposition to the Vietnam War. What began as a small antiwar movement in 1964–65 scaled up as the war escalated in 1966, giving rise to massive protests in 1967: 100,000 people marching in Washington, D.C., and half a million protesting in New York City. Passions in the antiwar movement reflected opposition in the public as a whole. Most Americans knew little about the war until the Johnson administration ramped up troop levels, but as it became clear that the war would be long and protracted, elite disaffection increased. And public opinion, dragged down by the unpopularity of the draft, began “a path of slow and steady decline” from which it would never recover. When citizens were asked in 1965 whether sending troops was a mistake, only 24 percent agreed. Three years on, 46 percent said yes. By 1970, the proportion rose to 57 percent, and it remained at around 60 percent until the end of the war.

LONG BUT PAINLESS

That public disaffection at home hastened the end of the Vietnam War is now widely acknowledged. By contrast, the American public has so far failed to turn up the heat on leaders to end the war in Afghanistan—even though few think that the country is winning. Protests against the war have been few and far between.

Popular anger is absent because the public is no longer directly affected by the war legally, personally, or financially. For one, today’s wars are less noticeable because they are increasingly unofficial. As the laws of war have proliferated, putting ever more constraints on what states at war can and cannot do, governments have looked for ways to sidestep this legal regime. At times, this simply means not signing international agreements: U.S. presidents of both parties have been unwilling to push for ratification of the Rome Statute, the treaty that founded the International Criminal Court, lest U.S. military personnel abroad be prosecuted unjustly. More often, however, states avoid stepping over any bright lines that put them unequivocally in the legal domain of war. As a result, the United States has gradually moved away from the legal formalities that had defined war for centuries. It has not issued a formal declaration of war since World War II. Congress did not invoke its power to declare war under Article 1, Section 8 of the U.S. Constitution to send troops to Afghanistan. Instead, it passed the sweeping Authorization for Use of Military Force, which has limped along since 2001 despite a constant barrage of bipartisan criticism. Likewise, the United States has not signed any formal peace agreements since the 1973 Paris Peace Accords—a trend that bodes ill for negotiations with the Taliban. Because such treaties have become less frequent, citizens no longer expect a formal end to war. Today’s informal wars are more easily normalized and even obscured from public view, removing some of the pressure to conclude them at all.

Second, most U.S. citizens no longer bear the physical costs of war personally. The end of conscription and the creation of an all-volunteer military in the 1970s have led to an opt-in system and a growing gap between most citizens and the military. In 1980, 18 percent of the population were veterans. By 2016, that number was down to 7 percent, which means that the average person today is far less likely to have experienced war. And the fact that not even one in 200 U.S. citizens serves in the military today means that few people directly know someone on active duty. Today’s public is more insulated from the human costs of war than previous generations.

Third, the nature of those physical costs has changed. Nonfatal casualties have almost always outnumbered fatal casualties in war, but this gap is increasingly stark for the United States today. For every U.S. soldier who died during World War II, four others were wounded. This wounded-to-killed ratio mostly held steady through Korea and Vietnam. In Afghanistan, however, it has more than doubled, and there are now ten wounded soldiers for every fatality. That media and polling organizations tend to focus on fatalities rather than the injured obscures this particular cost of war.

Today’s public is more insulated from the human costs of war than previous generations.

Finally, war no longer has the direct financial impact on U.S. citizens that it once did. Up until the Vietnam War, the United States levied war taxes. As a result, the public was patently aware of the costs of the war, and when citizens felt that a military campaign was no longer worth the costs they personally had to bear, they pressured leaders to bring it to a close. Tax hikes in 1968 to fund the fight in Vietnam were not the only reason millions took to the streets, but they were clearly a contributing factor. Based on official estimates, the war in Afghanistan had cost $714 billion by 2017 and continues to cost about $45 billion per year. But taxpayers wouldn’t know it, since these costs are just added to the national debt. Because the war is but one source among many to blame for the growing mountain of U.S. debt, its financial impact is easily overlooked.

All of these changes—legal, civil-military, and financial—are unlikely to reverse themselves anytime soon, which means that the way Americans feel the effect of conflict is unlikely to change either. But without being confronted with the grim realities of war, the public is unlikely to exercise the levers of accountability that it did in the past by voicing opposition and pressuring leaders to bring a close to the war. And without pressure from below, Congress is unlikely to act. War without end will be not the exception but the rule.