A recent New York Times editorial cast a skeptical eye toward the many calls for huge increases in U.S. military spending. “Giving the Pentagon a blank check does not ensure security,” the Times editors observed. “It got most of what it wanted in the decade after 9/11, yet America still struggles to keep Afghanistan and Iraq from falling to insurgents.”

Why do we spend so much, and appear to get so little?

One reason is our enthusiasm for using technology to solve problems that defy technological solutions. There’s an understandable tendency to focus on the whiz-bang aspects of America’s military hardware, from drones and precision-guided munitions, all the way down to the gear carried by the typical grunt. Fixating merely on the U.S. military’s capabilities could lead to overconfidence: “How can we lose?”

At least, that’s what we used to think. Now, after Iraq and Afghanistan, and Libya and Yemen (bet you forgot that one, and our other invisible wars), you’re more likely to hear “Why don’t we win?” It turns out that technology is not the critical factor behind a country’s success or failure in war. And, in fairness, it rarely has been. We also have to account for the intensity of an aggressor’s desire to win, and the victim’s desire to avoid defeat.

To be sure, colonial masters of old often managed to wreak horrific destruction on highly motivated but outgunned “indigs.” Think Omdurman (1898). In a number of cases, very small numbers of foreign overlords were able to subdue huge populations of resentful but fearful subjects. The restless natives would rise up, kill a few foreigners, thus inviting a more brutal crackdown. Then the pattern repeated. For centuries.

Political entities—from the clan and tribe to the nation-state—grew richer by conquering foreign peoples and taking their stuff. In more recent times, we’ve figured out other ways to achieve prosperity. Unabashed imperialism finds few adherents today. Evolving norms favor self-determination and respect for human rights. Equally important, I think, are the rising costs and declining gains of military intervention.

The wider availability of destructive technologies has helped to narrow the gap between the strong and the weak, and thus changed the cost-benefit equation. The proliferation—and crucially, convergence—of new technologies have steadily pushed the means of destruction down the continuum from large states, to small states, to groups and now even to individuals.

In a recent Cato paper, “Technologies Converge and Power Diffuses: The Evolution of Small, Smart, and Cheap Weapons,” the National Defense University’s T.X. Hammes observes that “dramatic improvements in robotics, artificial intelligence, materials, additive manufacturing (also known as 3D printing), and nanoenergetics are dramatically changing the character of conflict in all domains.” He anticipates that this technological evolution will change the way that the U.S. military fights its wars. “The proliferation of these capabilities will greatly complicate U.S. responses to various crises and will reduce our ability to influence events with military force,” he writes.

Hammes takes particular note of four factors—“the loss of immunity to attack, the tactical dominance of defense, the return of mass, and a requirement to mobilize”—that, he predicts, “will have direct strategic impact on the United States.” The ability of others to raise the costs of U.S. actions, and even retaliate directly against the U.S. homeland, might cause us to think more carefully about which wars we choose to fight in the first place.

Hammes will be at Cato to talk about his paper next week. He will be joined by CNAS’s Jerry Hendrix, and Andrew Philip Hunter from the Center for Strategic and International Studies, who are expected to comment on and critique his findings. As moderator, I’m going to press all of the participants to explain how the U.S. military’s current acquisition plans address this technological evolution, and whether the Pentagon’s global posture and deployment cycles are properly accounting for a prospective sea change in the offense-defense balance.

Christopher A. Preble is vice president for defense and foreign policy studies at the Cato Institute.

Image: Flickr/U.S. Army.