The New York Times | Loren DeJonge Schulman and Paul Scharre: Hundreds of our troops suffered brain trauma. We need to reconsider the costs of military interventions.

Over 100 American soldiers have been treated for traumatic brain injuries following Iran�s missile strike on Al Asad Air Base in western Iraq. The strike came in retaliation for the killing of Qassim Suleimani, the Iranian Quds Force commander, which has become a rhetorical staple of President Trump�s re-election campaign.

At the time, most of the American reaction to the strike � which included about a dozen ballistic missiles, some carrying upward of 1,100 pounds of high explosives � was muted gratitude that it was limited, there were no American casualties, and there would be no spiral of escalation.

But we soon learned that numerous American servicemembers were being treated for brain trauma. The Pentagon�s climbing numbers and mixed messages on the seriousness of the injuries show how far the military has come in responding to traumatic brain injuries (T.B.I.s) � but more important, how far it still has to go.

It is also a warning about how Americans weigh the costs of military interventions, which at best reflects only the headlines of conflict and rarely considers the long-term effects.

The creep of reports is not surprising for an injury as insidious as T.B.I. The symptoms of mild T.B.I. can be subtle, and diagnosis can take weeks or months. The fact that more than 100 troops have been found to have T.B.I. from the attack so quickly is a sign that the military�s system for screening and identifying troops with the trauma is functioning.

What is still broken is how both the president and defense leaders characterize the scope and impact of brain trauma or weigh the need to mitigate its effects. In the field, American forces understand the importance of immediately examining personnel exposed to explosions for brain injury and the urgency of prevention and treatment.

But in Washington, such understanding is far behind, as we saw in the president�s most likely calculated determination, shortly after the strikes, that the injuries were �not very serious.�

The Departments of Defense and Veterans Affairs have come a long way in their ability to diagnose the injury and offer treatment, but they continue to fall short on other measures needed to combat T.B.I.

In 2017, Congress mandated that the Defense Department establish a program to monitor and record blast pressure exposure for any servicemembers who may experience a blast in training or combat. A wearable blast gauge developed by DARPA in 2011 makes it possible to quantify blast pressure; that information helps to better understand the relationship between blast pressure and T.B.I., and identify troops who may be at risk for future injuries.

If troops in the missile attack had been wearing blast gauges, we would have quantifiable data on the amount of blast pressure they�d been exposed to � both for those who developed T.B.I. and those who did not. This would help the Defense Department better understand what level or type of exposure is problematic and inform designs for improved protective measures � helmets, bunkers or walls � against future attacks.

As a result of two years of bureaucratic foot-dragging inside the Defense Department, none of the troops hit by the Iranian missile attack were wearing the gauges.

The Iranian ballistic missile strikes could have caused brain trauma through a variety of mechanisms:

The primary mechanism is a wall of blast pressure from an explosion. Even relatively low levels of blast exposure can result in temporary cognitive deficits.

A secondary mechanism: Wind rushes to fill the vacuum left by the pressure wave. This can hurl shrapnel and fragments.

A tertiary mechanism: People or things can be thrown by this wind, leading to impact concussions.

A quaternary mechanism: Fires, toxic gases, burns or crashes can follow.

The non-primary mechanisms of injury are relatively easy to understand and protect against through traditional means such as body armor, helmets and fire-resistant uniforms.

The primary mechanism of injury � the blast pressure wave itself � is less understood. We don�t know whether servicemembers at Al Asad were injured by the blast pressure directly rather than being knocked over and hitting their heads. If Defense Department officials had done their jobs, that information could have been available.

Still, it�s clear that the Defense Department�s mandatory post-incident T.B.I. screening has advanced remarkably since the inconsistent mechanisms in the years of the Iraq and Afghanistan wars.

What has been slower to adjust is a culture that has approached concussions as something to be �shaken off� or worries that diagnoses may harm their careers.

Extensive public education has mitigated some of the cultural stigma of brain trauma diagnosis and treatment, but it still has a ways to go. This is why the public communications from the White House and Pentagon have been such a bumbling disaster.

The minimizing statements in the wake of the Iran missile strike by the president, Defense Secretary Mark Esper and Centcom contradict the department�s own extensive medical research on the severity of T.B.I. and the potential need for a lifetime of monitoring or intervention. Many initially judged these comments as part of the downward trend of transparency from the Defense Department. But slow acknowledgment is more likely a lingering hang-up from the invisibility of this injury that trickles down to both flawed short-term assessments and long-term understanding of costs and risks.

Such narrow lenses of the impacts of war pervade in politicians� talking points, public debate and even military training and planning.

The Defense Department needs to change its public reporting on brain trauma casualties. For too long, its official casualty statistics have significantly undercounted the true number of wounded personnel because they often miss individuals with T.B.I. As a result, the numbers severely underestimate the costs of today�s wars and the long-term interventions necessary to address them.

The Defense Department�s official count is 52,000 servicemembers wounded in the wars in Iraq and Afghanistan. Over 413,000 servicemembers have been diagnosed with T.B.I. since 2000. That figure combines both combat and noncombat causes. Yet the huge spike in brain trauma numbers in the years during and following the peak of the Iraq and Afghanistan wars speak to the volume of combat-related injuries. The true number of war wounded is most likely in the hundreds of thousands.

These misleading numbers are not a deliberate deception, but the result is the same: The American public is not being told the truth about the human cost of these wars in wounded Americans.

In response to public scrutiny, Secretary Esper recently stated: �We are still learning. There�s a lot more to be learned about these injuries.� It�s time to put that education into practice and start treating traumatic brain injury with the seriousness it deserves.

Loren DeJonge Schulman served in the Obama administration on the National Security Council staff and at the Department of Defense. Paul Scharre is a former Army Ranger who served in Iraq and Afghanistan, worked as a civilian in the Defense Department and is the author of �Army of None: Autonomous Weapons and the Future of War.� They are senior fellows at the Center for a New American Security.