What we call “modern warfare” didn’t come out of nowhere, it came out of a particular time (the late 19th century) and for a particular reason (the application of new ideas to military affairs). It wasn’t just the technology and new weapons that changed things as much as it was new ideas that dramatically changed the way the military thought about combat. The general public tends to know little about some of the key ideas that changed the way we fight wars.
Military thinking began to change profoundly in the late 19th century. Much of this was coming out of Germany and not all of it was recognized at the time. This included the use of simulation and modern organizational techniques. These innovations are most commonly known today as wargaming and the general staff system. Both of these were actually among the many new tools to be created as a result of the Scientific Revolution of the 18th and 19th centuries. In addition to a lot of new scientific knowledge, this revolution also produced modern concept like graduate school and scientific management (the modern corporation, creative destruction and how to adapt to constant change). All tese new concepts were most prominent in Germany and the military side of it was popularized by German historian and reserve officer Hans Delbruck. He pioneered the use of these new tools to the study of military history. He applied common sense and modern analytical tools (modern statistics also came out of the 19th century) to accounts of ancient warfare and clearly demonstrated what was real (or at least possible) about warfare in the distant past and what was not. Delbruck was one of many 19th century Germans who literally invented the modern world.
The Germans perfected many of the tools and techniques all military planners and staff officers came to use and take for granted and Delbruck explained it all to the general public as well as many senior members of the German government and industry. This was due to the fact that for Delbruck this was the continuation of a family tradition. The Delbrucks had advised Prussian Kings on matters of war for generations. The Delbrucks did this because they believed that if the king understood war in a fundamental sense then little (compared to its neighbors) Prussia would survive. The Delbrucks felt that the growth of democracy and literacy made it necessary to spread this knowledge to a wider audience because as the people became sovereign they must understand war. Hans Delbruck became the foremost military historian of his time. In addition to being a prolific writer on military matters (for professionals as well as the general public), he also founded the first chair of military history at a civilian university and edited the first defense affairs journal aimed at a civilian audience. This was revolutionary and made it easier for the general public to accept the dramatic changes in military affairs and warfare. There were many writers in other countries who followed Delbruck’s example and provided useful analysis while also educating those in government and the military as well as interested citizens.
Going into the 20th century there were some more dramatic new ideas that are less well known. Take the widespread (and continued) use of Operations research (OR). This is the use of quantitative techniques (statistics, etc.) to solve problems and help leaders make decisions. OR concepts have been around for centuries, but in the 1930s it came to be recognized as a distinct discipline and its tools were organized and applied systematically. OR was used extensively during World War II to solve numerous problems; everything from how best to use radar or hunt submarines to running factories and getting supplies to the troops efficiently. Following this wartime experience, there were even more numerous peacetime successes. Some of this was simply using OR to examine past military events so as to better understand them and thus be able to come up with better tactics, techniques and weapons. But the widest ranging use of OR was for solving business and social problems. This led to OR being called "Management Science."
Operations Research is, arguably, the most important scientific development of the 20th century. OR, like the earlier Scientific Method, is basically a management technique. Management is also a 20th century concept that gets little respect. In some respects, OR is the combination of management principles and the Scientific Method. Without the breakthroughs in management techniques, the enormous scientific progress of the 20th century would not have been possible. Without OR World War II and subsequent wars would have been messier, costlier and longer
All these changes indicated some fundamental shifts in how wars were found but without a war between anyone using these modern weapons it was hard to understand what had really changed. Then came the 1973 Arab-Israeli war. During that conflict the speed with which modern weapons and other systems could destroy the enemy and speed up combat shocked generals worldwide. At this point everyone began to ponder the impact of this transformation in the way wars were fought. The Russians concluded that speed in decision making would become decisive, as would the growing Western edge in precision weapons. The Russians proposed in the 1980s that computers be used more by commanders to speed up the planning and execution of battles. That took several more decades to become practical.
Meanwhile the destructive impact of all this new technology was, in part, explained in the 1960s by John Boyd, a U.S. Air Force officer. Boyd demonstrated how the speed of assessing a combat situation, developing a plan and executing was decisive in all forms of combat. Boyd came up with the OODA (observe, orient, decide, and act) loop, which could be applied to air, naval and ground combat. This made sense to World War II veterans who had witnessed the OODA loop in action. It resonated with the Russians as well because superior speed with OODA was a German specialty which the Russians never mastered as well as the Germans did during World War II. But by the 1980s some Russian theorists saw computers as a possible solution. Again, the West had a technological edge and from the end of the Cold War and into the 21st Century it was Westerners who made all this work in combat.
The impact of high speed warfare was demonstrated after September 11, 2001 when American forces used computerized data mining and analysis to speed up their OODA during counter-terrorism operations in Iraq. Thus the Sunni terrorists quickly learned that if an American raid was accompanied by intelligence specialists carrying biometric tools and comm links (to huge databases of information on known terrorists and their organizations) there would quickly be additional raids. A few new names found on one raid would spawn additional raids and within 24 hours large terrorist operations could be rolled up. Microsoft contributed by developing a thumb drive that could quickly extract useful data from a laptop while rough (but effective) machine translation of many Arabic documents could quickly provide more leads, locations and who or what to look for.
The wars in Iraq and Afghanistan produced even more adaptation of commercial tools and techniques and applied them to intelligence work and combat planning. Data mining and predictive analysis (computing what the enemy would do next using their past and current patterns) drives modern marketing and much else. The troops in Iraq and Afghanistan showed how it could be used to hunt down Islamic terrorists and destroy their networks.
In the works are revolutionary new robotics concepts and tools. Autonomous combat robots have already been around since World War II (the wake homing torpedo, for example) and have become, without much fanfare, more common. Now these technologies are beginning to enter air and ground combat in a big way. Thus the flood of new ideas that has accompanied new weapons and tech in general continues.
Dramatic change in warfare from one decade to the next has become the norm in the last century. People are still having a hard time getting used to and handling this high rate of change. That, so far, has been the only constant.