Technology is not the only variable RMAs require a convergence of technology, training, doctrine, and operational concepts, as well as a fundamental shift in underlying assumptions, to produce a new way of competing and fighting.

While the history of warfare is mostly evolutionary, certain technological advancements-such as gunpowder, aviation, and precision-guided munitions-have revolutionized warfare and reshaped military balances and the geopolitical landscape. These contemporary trends are best understood through the historical lens of revolutions in military affairs, or RMAs. This vision for the future balance of strategic forces should then enable defense and diplomatic officials to determine investment priorities accordingly and decide when and how to engage Russia and China to avoid strategic instability in this new era. To avoid falling behind, the United States must hedge against disruptive capabilities by modernizing its existing nuclear arsenal and undertaking a systematic review of strategic capabilities for the 2030s. But together, they will revolutionize the way that great powers deter and conduct war. Individually, these technologies are potent. The old model of strategic nuclear deterrence is increasingly threatened by a new suite of military technologies, from hypersonic missiles and advanced missile defenses to non-kinetic cyberattacks. If we are not attentive now, the United States may lose the ability to deter major attacks in coming years. Senior military leaders and pioneering scholars believe a new technological revolution is now unfolding, and they are right. Nuclear weapons are no longer enough to sustain U.S.

Weapons of the third era