Great wars are tragedies for the people and the countries that wage them. They are also transforming the way the world prepares for conflict with far-reaching consequences for global security. Britain, France, and Germany sent observers to the American Civil War to study battles like Gettysburg. The tank duels of the Yom Kippur War in 1973 accelerated the change in the US military, from the force it had lost in Vietnam to the one that crushed Iraq in 1991. That campaign, in turn, led Chinese to reshape the People’s Liberation Army into the formidable force it is today.

The war in Ukraine is the largest in Europe since 1945. It will mark the way of understanding combat for decades to come. It has shattered all illusions about the possibility that modern conflict could be limited to counterinsurgency campaigns or evolve into low-casualty fighting in cyberspace. Instead, it points to a new kind of high-intensity warfare that combines cutting-edge technology with industrial-scale killing and ammunition consumption, while drawing civilians, allies, and private companies into it. There is no doubt that autocratic regimes are considering how to gain an advantage in any future conflict. Rather than recoil from death and destruction, liberal societies need to recognize that wars between industrialized economies are a very real prospect, and they need to start preparing.

The bloody Ukrainian fighting scenes contain three great lessons. The first is that the battlefield is becoming transparent. Forget binoculars or maps and think about all-seeing sensors from satellites and fleets of drones. Cheap and ubiquitous, they provide data that is processed by increasingly sophisticated algorithms capable of distinguishing a needle in a haystack: the signal from a Russian general’s cell phone, for example, or the outline of a camouflaged tank. That information can then be transmitted by satellites to a simple soldier on the front lines or used to target artillery and rockets with unprecedented precision and range.

That hyper-transparency means that the wars of the future will revolve around recognition. The priorities will be to detect the enemy first, before being detected by him; blind their sensors, be they drones or satellites; and disrupt their means of sending data across the battlefield, whether through cyberattacks, electronic warfare, or old-fashioned explosives. Troops will have to develop new ways of fighting based on mobility, dispersal, concealment, and deception. Large armies that do not invest in new technologies or develop new doctrines will be overwhelmed by smaller ones that do.

Even in the age of artificial intelligence, the second lesson is that war can still involve an immense physical mass of hundreds of thousands of human beings and millions of machines and munitions. Casualties in the Ukraine have been severe: the ability to see targets and hit them with precision skyrockets the death toll. To adapt, the soldiers have removed mountains of mud and dug trenches worthy of Verdun or Passchendaele. The consumption of ammunition and equipment is staggering: Russia has fired 10 million shells in a year. Ukraine loses 10,000 drones a month. It is asking its allies for traditional cluster munitions to sustain the counteroffensive.

Over time, technology could change the way that material “mass” requirement is met and maintained. On June 30th, General Mark Milley, the highest ranking US military officer, predicted that one third of advanced military forces would be robotic within 10-15 years: think pilotless air forces and unmanned tanks. Now, armies have to be able to fight both in this decade and in the next. That means replenishing arsenals to prepare for high attrition rates, building the industrial capacity to manufacture materiel on a much larger scale, and ensuring that armies have reserves of human resources. The NATO summit on July 11 and 12 will constitute a test for Western countries that will show whether or not they can continue to revitalize their alliance for these purposes.

The third lesson – also valid for much of the 20th century – is that the frontier of a great war is wide and indistinct. The Western conflicts in Afghanistan and Iraq were fought by small professional armies and did not impose a great burden on the civilians of Western countries (but often much pain on the local population). In Ukraine, civilians have been caught up in the war as victims (more than 9,000 have died), but also as participants: a grandmother from the provinces can help guide artillery fire through a mobile app. And beyond the old military-industrial complex, a new cohort of private companies has proven crucial. Ukrainian battlefield software is hosted on the cloud servers of big tech companies abroad; Finnish companies provide target data and US satellite communications. A network of allies, with varying levels of involvement, has helped supply Ukraine and enforce the sanctions and embargo on Russian trade.

The new frontiers create unprecedented problems. The increasing participation of civilians raises legal and ethical questions. Private companies located outside the conflict zone may be the object of virtual or armed attacks. As new companies appear, governments need to ensure that none of them are a point of failure. No two wars are the same. Between India and China a fight can take place on the roof of the world. A Sino-American standoff over Taiwan will mean more air and naval power, long-range missiles and trade disruptions. The mutual threat of nuclear use has likely worked to limit escalation in Ukraine: NATO has not directly confronted a nuclear-armed enemy, and Russian threats have so far been bluster. However, in a fight over Taiwan, the US and China would be tempted to attack each other in space, which could lead to a nuclear escalation; especially if early warning and command and control satellites are disabled.

For liberal societies, the temptation is to turn away from the horrors of Ukraine and the enormous cost and effort involved in modernizing their armed forces. However, they cannot assume that such a conflict, between large industrialized economies, will be an isolated event. An autocratic and unstable Russia would pose a threat to the West for decades. China’s growing military weight is a destabilizing factor in Asia, and a global resurgence of autocracy will make conflict more likely. Armies that do not learn the lessons of the new kind of industrial warfare we are witnessing in the Ukraine risk being defeated by those that do.

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Translation: Juan Gabriel López Guix