Engaged in Iraq, fighting in Afghanistan and focused on restraining the nuclear weapons ambitions of Iran and North Korea, the United States has quite a bit on its national security plate.

At the same time, decisions must be made on future military capabilities with the realization that budgets can no longer sustain the huge appetite for resources that our forces have required in fighting these conflicts for nearly a decade. In making these decisions, choices will be dramatically affected by four revolutions.

The word “revolution” is itself controversial and too often used promiscuously. For more than 20 years the “revolution in military affairs” dominated much of the past thinking about defense. That revolution was driven largely by technology and the ability to achieve precision targeting in virtually all conditions of conventional war.

For most of history, military strategists have argued for forces and capabilities designed to fight other more or less like forces in wars in which armies and navies faced off against each other. Hence, the umbilical cord between this concept of war and the forces required to fight those wars was not susceptible to being severed. Today, the first revolution is driven by attempts to slice this centuries-old umbilical and replace it with the demands of irregular and hybrid warfare exemplified by conflicts in Iraq, Afghanistan, Lebanon and Chechnya. (As an aside, I hope we can find a better term than hybrid – it reminds me of a Toyota Prius.)

The programmatic cuts announced earlier this year by Defense Secretary Robert Gates may prove to be the opening salvos of this revolution in which the United States is, correctly in my view, removing the chokehold high-intensity conventional war has had on force planning. The same trend is clear in the United Kingdom, but where defense spending cuts are currently far more pronounced and have sparked intense internecine inter-service fights.

The second revolution is both corollary and catalyst of the first. Wars, as Clausewitz reminds us, are clashes of will and hence entirely human endeavors among people. For most of history, in military terms, people meant opposing armies and organized forces. But, as Lenin, Mao and retired British Gen. Sir Rupert Smith in his powerful book “The Utility of Force” have shown, today war is about people from the elite leadership to the most downtrodden peasant. “Hearts and minds” are an overworked expression of this struggle. In more appropriate terms, without the support of the people, the most successful of military operations such as Operation Iraq Freedom can bring only tactical and not strategic and political victory.

The third revolution is really a counterrevolution. Warfare is too easily and readily divided into components of land, sea, air, space and cyber. These distinctions lead to the false presumption that war can be neatly categorized accordingly. Perhaps when armies fought armies and even allowing the reach of joint operations to integrate these different forces, those distinctions were acceptable. However, when the strategic center of gravity is people, we need to think again how best to organize to achieve our aims that go far beyond and do not involve merely destroying an enemy army.

Against these revolutions, the fourth is the most powerful and stunning. This is the revolution in knowledge. This revolution uses Moore’s Law that chip and computer capacity will double every 18-24 months as one of the engines that produce every few years more knowledge than existed in all prior history. Of its consequences, two are especially relevant to dealing with the threats and challenges of irregular and hybrid war.

The technical knowledge that is being accumulated is crucial to success in dealing with these threats and realities and is a double-edged sword. Our adversaries are also privy to much or all of this knowledge and in some cases are more agile and faster in exploiting it. The other consequence is in recruiting, educating, training and preparing our forces for these environments.

Knowledge is central to learning, education, training and experience. As long as armies have been trained or sometimes educated, this process has been vertical, that is as one progresses up the ranks, one is provided the learning and knowledge deemed appropriate. As a result, lieutenants and sergeants do not go to war colleges. Yet, given responsibilities in the field and the nature of insurgent war, these younger and more junior ranks may need precisely the learning and knowledge provided to colonels and generals.

One conclusion is clear. To cope with these revolutions, knowledge and learning are perhaps the most effective tools. To ensure that these are part of the military kit and in many ways more important than the most advanced fighter aircraft and armor will require a real and separate revolution. Otherwise, success will prove very illusive.

Harlan Ullman is a member of the Atlantic Council’s Strategic Advisors Group and a Distinguished Senior Fellow at the National Defense University.  This essay was originally published as “Four Revolutions” in the Outside View column, part of UPI‘s Emerging Threats analysis section.