Second, war is human. People fight today for the same fundamental reasons the Greek historian Thucydides identified nearly 2,500 years ago: fear, honor and interest. But in the years preceding our last two wars, thinking about defense undervalued the human as well as the political aspects of war. Although combat operations unseated the Taliban and the Saddam Hussein regime, a poor understanding of the recent histories of the Afghan and Iraqi peoples undermined efforts to consolidate early battlefield gains into lasting security.

Over time, American forces learned that an appreciation of the fears, interests and sense of honor among Afghanistan’s and Iraq’s citizens was critical to breaking cycles of violence and helping to move their communities toward making political accommodations that isolated extremists. Reinforced security efforts, in Iraq after 2007 and Afghanistan after 2010, tried to allay fears of minorities, preserve each group’s sense of honor and convince communities that they could best protect and advance their interests through politics rather than through violence.

The hard-learned lesson: Defense concepts must consider social, economic and historical factors that constitute the human dimension of war.

THIRD, war is uncertain, precisely because it is political and human. The dominant assumption of the “Revolution in Military Affairs” was that information would be the key to victory. Concepts of “network-centric warfare,” “rapid, decisive operations,” “shock and awe” and “full-spectrum dominance” suggested that near-perfect intelligence would enable precise military operations and point a straight line to success. But in Afghanistan and Iraq, planning did not account for adaptations and initiatives by the enemy. American forces, deployed initially in insufficient numbers to keep pace with the evolution of those conflicts, struggled to maintain security. The lesson: The wars in Iraq and Afghanistan, like all wars, were contests of will that unleashed dynamics that made future events impossible to predict.

Fortunately, in Afghanistan and Iraq, American forces adapted. For example, in 2005, in western Nineveh Province, our enemies had pitted sectarian communities against one another in a bloody civil war. In the city of Tal Afar, our cavalry regiment first sought to understand the complex environment while building trust with local Iraqi security forces and a beleaguered population. Alongside United States Special Forces and Iraqi soldiers, our troops sought not only to fight the enemy, but also to build security for civilians and promote conflict resolution among competing groups. As Tal Afar’s mayor, Najim Abdullah Abid al-Jibouri, recalled, “Our city was the main base of operations for Abu Musab al-Zarqawi ...Our people were barricaded in their homes out of fear; death awaited them around every corner.” But when the Americans came, he added, “With the skill and precision of surgeons they dealt with the terrorist cancers in the city without causing unnecessary damage.”

What we learned: American forces must cope with the political and human dynamics of war in complex, uncertain environments. Wars like those in Afghanistan and Iraq cannot be waged remotely.

Budget pressures and persistent fascination with technology have led some to declare an end to war as we know it. While emerging technologies are essential for military effectiveness, concepts that rely only on those technologies, including precision strikes, raids or other means of targeting enemies, confuse military activity with progress toward larger wartime goals. We must not equate military capabilities with strategy. Achieving our aims in war will demand forces who can reassure allies and protect populations, as well as identify and defeat elusive enemies.