The list of ongoing armed conflicts in the worlds is long (see, for example, here) and has been long for centuries. There are many websites and research institutes that keep track of their number, the parties involved, the main issues, et cetera. There are many different definitions of war and armed conflict. Here, wars are simply defined as armed conflicts with participation of one or more states whose sovereignty is internationally recognized, whereas armed conflicts do not require state involvement. Armed conflicts have always been around in great numbers, often state-sponsored, for example the numerous and seemingly never ending conflicts in the Middle East, or recently in Northern Africa following the so-called Arab Spring. The recent collapse of Libya into civil war may serve as evidence.
The number of interstate wars dramatically decreased after the end of the Cold war, giving stimulus to loads of academic papers about democratic or liberal peace. Yet this era might well be over, given the situation in the Ukraine, but also many explosive situations in North-East Asia and South-East Asia.
Academic research resulted in a long and varied list of possible causes for wars and armed conflicts. Think for example of geopolitical factors (land, borders), natural resources (oil, gas, mines), population related issues (minorities of other countries living in a particular area, people demanding their own country), religious conflicts, the protection of one’s own people abroad, global political reasons (participation is war as a consequence of an alliance, or to preserve the balance of power), humanitarian reasons (genocide), et cetera. In contrast to popular belief, wars and conflicts are often multicausal, so there is not just a single but a number of reasons for their initiation and continuation.
War and conflict are the result of human action. Despite all the peace talks and agreements, treaties, other forms of international law, arbitration, the work of international organizations, and the pre-emptive actions by great powers in world politics, war and armed conflicts have never been eradicated. So it seems fair to assume this has something to do with human nature as well. Here the literature is much smaller, perhaps as a consequence of the dominant belief (at least in the Western world) in rational human beings capable to overcome war and armed conflict. As a matter of fact international relations as an academic discipline owes much of its origin to this idea. After the First World War many academic positions and departments were established, with the explicit aim to search for ways to prevent such disasters from happening again. Unsurprisingly, without much result.
The ‘human are guided by rationality thesis’ has been defended by many liberals in the American tradition (also known as social liberals or high liberals) and some libertarians as well. In fact most liberal IR theories are based on this idea. However, the idea that that human beings and conflict cannot be separated has been prominent in the writings of classical liberals such as Hume, Smith, Hayek and Mises, but also by Ayn Rand. Interestingly, for this latter position there is now increasing evidence from other academic disciplines, such as psychology and neurosciences. For example the famous book Thinking Fast and Slow by Daniel Kahneman, or more specifically War and Human Nature by Stephen Peter Rosen, Thayer’s Darwin and International Relations, or Donelan’s Honor in Foreign Policy.
While much more work needs to be done in this field, it is safe to conclude that liberals should not think about how to abolish war. Instead, the relevant question is how to deal and limit the inevitable occurrence and continuance of war and armed conflicts.