How Ukraine Has Changed the Character of War

My assessment in Foreign Affairs at the three year mark of the Russian large-scale invasion of how some elements of the war in Ukraine will impact on the character of future wars.

Some time ago, I pitched a story to Foreign Affairs about the changes in warfare we have witnessed over the three years since the Russian large-scale invasion of Ukraine. Too many assessments of the war pose arguments about changes in the character and nature of war through the lens of only studying this war. That is insufficient to truly understand the many currents that influence this war, and the direction of war in general. There are many aspects of this war that are not new: surprise, the need for good leadership, the importance of mass and industrial production among them. As someone who has studied war as a phenomenon for a long time, has participated in some wars and studied many others, I wanted to provide an assessment of how Ukraine is changing some elements of the character of war, and what it means for the rest of us. Enjoy.

Very few people predicted that a long, high-intensity war in Europe was possible in the twenty-first century. But for three bloody years, Russia’s invasion of Ukraine has delivered exactly that. Hundreds of thousands of Russians and Ukrainians have died in the fighting. Many more have been injured. Entire towns have been reduced to ruin or cut apart by trenches, in a grim callback to World War I.

Now, the war in Ukraine has reached an apparent stasis. Russia continues to take small parcels of territory along the eastern front, but only by incurring unsustainably high casualties. The two countries have achieved parity when it comes to their long-range strike capabilities. Both have become fully mobilized war nations, allowing Russia to bounce back from its initial failures and allowing Ukraine, a smaller country, to keep fighting on through grievous losses. In the immediate future, then, the frontlines are likely to remain relatively stagnant. There will be no major breakthroughs.

U.S. President Donald Trump, however, has promised to end the war, reaching out to Moscow and setting up negotiations between American and Russian officials. In theory, these talks could turn 2025 into a decisive year for conflict. But there is no reason to think that interventions by Washington’s new sheriff will prove transformative, especially given that Kyiv has been frozen out of the conversation. The Trump administration is already discovering that the complexities of this conflict will preclude quick solutions. Trump has acceded to Russian President Vladimir Putin’s demand that Ukraine be locked out of NATO and Russia granted a sphere of influence. But Putin has given nothing in return, retaining his maximalist demands about Ukrainian disarmament and subjugation. The result could lead Washington to walk away and resume support for Kyiv.

But regardless of the outcome of the negotiations, the war in Ukraine has already changed conflict around the world. It has proven that today, drones, AI, and other kinds of advanced technology are important arbiters of success on the ground and in the air. It has demonstrated that warring countries are accelerating the pace of their battlefield and strategic adaptation. And it has highlighted the tensions between soldiers and civilians—and the weaknesses in current theories of how the two interact in high-tech conflict. In doing all of this, the war has exposed the shortfalls of Western militaries.

There are few certainties about how the invasion will play out, especially given Trump’s desire to force a resolution. But Putin will almost certainly continue to try to seize or destroy as much of Ukraine as possible in advance of any peace deal. (With a buildup of Russian troops in Belarus, he is clearly preparing to threaten other European countries, too.) Ukraine, meanwhile, is contemplating whether it can fight on without American help. Ukrainian President Volodymyr Zelensky recently pegged those odds as “low.” Yet if the Putin-Trump deal is intolerable to the government and people of Ukraine, the country will have to.

The conflict between Russia and Ukraine has changed much about how politicians, strategists, and civilian populations understand war. But one shift is especially obvious: autonomous and remotely operated vehicles have become a mandatory component of armies, navies, and air forces. Across the ground, maritime, and aerial domains, drones are being integrated into both the Russian and the Ukrainian militaries at remarkable speed. The number of aerial drones used in the war has expanded from hundreds to thousands to hundreds of thousands. Russia and Ukraine now each have the capacity to build millions of drones every year.

Both countries have been innovative in their use of drones. On the ground, each is pioneering new approaches to old missions by using drones for surveillance, logistical support, evacuating injured troops, laying and clearing mines, and, of course, launching attacks. But the Ukrainians have been extraordinarily creative. In the maritime domain, Ukraine defeated the Russian Black Sea Fleet with a variety of domestically designed semisubmersible, remotely operated vehicles. More recently, the country has pioneered coupling different drone systems for specific missions. In late 2024, Ukraine used maritime drones as launch pads for aerial drones to attack Russian oil rigs and surveillance systems in the Black Sea. In December, Ukraine paired ground and aerial systems in the battle for the village of Lyptsi, near Kharkiv, in which robotic weapons alone attacked and seized a fortified Russian defensive position for the first time, forcing the infantry manning it to retreat. And in January, the Ukrainians again launched aerial drones from maritime drones to attack Russian air defenses in occupied Kherson.

Unmanned vehicles will remain critical to how Ukraine keeps up with the Russians. In part through its use of drones, over the past three years Ukraine has built a long-range strike complex that now operates in parity with the Russian system. Kyiv is adapting and improving its strike capacity faster than Moscow is. As a result, Ukraine’s campaign against energy, military, and defense-industry targets is likely to hurt Russia more in 2025 than it has in the preceding three years. But in the future, both Ukraine and Russia are likely to more closely integrate humans and drones in military units. This will drive further innovation in human-drone tactics and will require new kinds of training for soldiers and military leaders.

The tentacles of technological insertions reach even further than drones. They have enabled the meshing of artificial intelligence, civil and military sensor networks, and the democratization of battlefield information. AI systems can help drones pick and confirm targets by combing through open-source sensors and intelligence analyses and then combining this information with military intelligence.

These new technologies have also driven other, new ways of thinking about military tactics and structures. Just as drones will force the restructuring of existing military organizations and lead to the formation of new ones, AI will fundamentally change how officials make battlefield and strategic decisions. Although current algorithms must be improved to reduce hallucinations—when an AI delivers false or misleading information—and gain more trust from military commanders, AI systems are improving. The Israel Defense Forces have recently demonstrated the utility of AI support for target assessment, weapons selection, and speeding up human decision-making.

New technology has led to adaptation. AI, for example, has helped both Russia and Ukraine close the time between when an enemy target is detected and when it can be attacked. The Ukrainians initially led the way with closing this “detection-to-destruction gap,” but Russia has caught up. Such innovation is not in itself surprising: learning and adaptation has always been part of warfare.

But the pace is quickening. Consider that it took years for the U.S. military to adapt to the physical and intellectual demands of counterinsurgency operations in Afghanistan and Iraq a couple of decades ago but only months for Ukraine to develop its maritime drone strike fleet. Ukraine now updates some of its algorithms and drone communications software daily. And the learning and adaptation battle between Russia and Ukraine is continuing to accelerate as each side improves its ability to learn and share lessons between the battlefield and its national industrial bases. In doing so, these countries are underscoring an old truth: the military institutions that win wars are never the same organizations that begin them. Armed forces that can systemically and strategically adapt will have greater power in both war and peace.

The changes in Ukraine will affect every military institution in the coming decade. Western countries, in particular, will face a reckoning about their military postures. They do so just as Trump and his administration are calling old alliances into question, creating even more uncertainty and demanding a massive realignment of military structures in Europe and the Pacific.

You can read the full article here at Foreign Affairs.