The U.S. military understood the importance of STEM long before it became the most coveted acronym in education.

Recognizing their critical skills in the conduct of war, George Washington appointed the first engineering officers to the Revolutionary Army on June 16, 1775.

Military historian Ian Hope describes how “American military thinking emerged in the young republic solidly committed to … the discovery of scientific components of war, with complete faith in the power of reason and with an unprecedented belief in the utility of mathematics as key to all scientific endeavors.”

That philosophy helped guide the development of the country’s military academies. In 1802, President Thomas Jefferson signed legislation establishing West Point as the nation’s first engineering school. Its first superintendent, Lt. Col. Jonathan Williams, declared that “we must always have it in view that our officers are to be men of science.” Superintendent Sylvanus Thayer, often called the “father” of the military academy, later grounded the school’s curriculum firmly in mathematics.

The academy remained true to that mission when I was at West Point in the 1960s. We had math every morning, beginning with a slide-rule drill, six days a week for our entire first year. Upon graduation, we could select, according to our place in the order of merit, which of the (then five) branches of combat arms we wanted to join. The quota for the Corps of Engineers always ran out first. (I chose Infantry, which never ran out.) Today, the engineering programs at the service academies are among the best in the country.

There’s an understandable premium on scientific expertise at the Pentagon, too. When I was an assistant secretary of the Air Force in the early 1980s, the defense secretary was a physicist. The current secretary also is a physicist. A technical background makes sense for the leader of an institution responsible for so many complex platforms, including nuclear and satellite systems. The threat of terrorism, the operation of drones and the growing challenge of cyberwarfare further illustrate the demand for uniformed leaders to have a sound grasp of technical fields.

But even in an age of highly sophisticated warfare, our military leaders should not be too narrowly focused on STEM. If we want leaders who communicate clearly, solve problems creatively and appreciate cultural differences in theaters where they operate, studying the humanities is just as important as science, technology, engineering and math.

When I attended Ranger and Airborne schools, a mandatory catchphrase was “move, shoot and communicate.” Communication was always a critical component of military tactics, and the more complicated combat has become, the more important it is to ensure clarity of thought and expression that relies upon a grounding in softer disciplines.

Those who lead need to be ready for the moments when they must summon their troops — who may be hurt or drained by fatigue — to rise, to respond, to prevail against the odds. That power doesn’t come out of the barrel of a gun or the insignia of rank, much less a math formula. It comes from an understanding of human motivation that can be gained by studying psychology, by analyzing history, by reading great literature. Military leaders should know that the familiar notion of troops as a “band of brothers” originates with the stirring speech Shakespeare’s Henry V delivers to his outnumbered forces at the Battle of Agincourt.

Military leaders also need to be agile thinkers who can assess an unfamiliar situation and strategize a plan. That might require a cost-benefit analysis, but it also requires an understanding that not everything can be quantified. As a special assistant to Gen. William Westmoreland in 1968, I became familiar with the Hamlet Evaluation System, a monthly report that quantified the level of “pacification” by color-coding each village in South Vietnam. When attacks throughout the country erupted during the Tet Offensive, the HES reports were quickly considered an unreliable gauge. By contrast, the success of the 2007 surge in the Iraq War was under the command of Gen. David Petraeus, who, with a PhD in international relations, employed a counterinsurgency strategy based on the Army manual he co-wrote that emphasized leaders’ flexibility and adaptability in dealing with indigenous populations.

The utility of non-STEM learning is further reflected in the nature of mission assignments. President Lyndon Johnson said victory in Vietnam would depend on our winning the “hearts and minds” of the Vietnamese, an objective necessitating education in relevant history, language and culture for military personnel assigned to advisory roles. That remains true in many conflicts today.

The mission of the military has expanded in ways that make a liberal arts background even more important. When Vice President Biden spoke to the graduating class at West Point in May, he told them: “You’re gonna need every tool your predecessors possessed … but you’re gonna need more.” He went on to talk about “next-generation technologies, like unmanned systems and autonomous machines” and the need to “dominate the cyber realm.” But he also spoke about “building the capacity of emerging countries” and managing “humanitarian crises posed by climate change, mass migration and the spread of infectious disease.” To take on these new challenges, rising military leaders benefit from a familiarity with foreign policy, public health and international development issues.

The slide rule my classmates and I struggled to master every day passed out of use a long time ago. But the service academies should be cautious about what they put in its place. If they can expose the minds of officers in training with the right ideas and the right spirit, they will cultivate a cadre of tomorrow’s military leaders who will best serve the national interest.