Conflicts are defined, in large part, by how they are fought and their technologies. The First World War we associate with gas and tanks and the earliest use of airpower; the Second World War with strategic bombing and the first use of nuclear weapons. Those technologies help define us as human beings, shape our experience and politics, mould our present fears. So what of the way our conflicts are being fought today?

Last week, David Rothkopf, editor at large at Foreign Affairs and a visiting scholar at the Carnegie Endowment for International Peace, adopted a startling new construction. In an article inspired by the revelation that a secretive Chinese People's Army unit had hacked many of Washington's public institutions, he suggested we are now living through a "Cool War".

He defines this state of conflict in two ways. First, it involves "almost constant offensive measures that, while falling short of actual warfare, regularly seek to damage or weaken rivals or gain an edge through violations of sovereignty and penetration of defences". Its second defining feature, not least regarding the revelations over Chinese cyber warfare efforts, is its deployment of "cutting edge" technologies, which are changing the way in which many conflicts and tensions are being played out.

"The purpose of the Cold War," he says, "was to gain an advantage come the next hot war or, possibly, to forestall it. The purpose of Cool War is to be able to strike out constantly without triggering hot war while making hot wars less desirable (much as did nuclear technology during Cold War days) or even necessary."

Rothkopf is not the first to suggest the emergence of a Cool War. The phrase was coined in the late 1970s by the science fiction novelist Frederik Pohl, whose dystopian book of that title envisioned a free-for-all of national hit teams launching computer viruses to crash stock markets and where sabotage replaced combat.

Late last year, the European Journal of International Law had its own stab at defining it, suggesting, just as in the Cold War, that an important factor is a growing new intransigence in international bodies.

"We do not find this or that superpower facing each other with arsenals at the ready, and the talk is very different. And yet, from one point of tension and global threat to another, whether Africa, the Mid East (Syria, Iran), south-east Asia, the Koreas, Japan and China, the Security Council [and] regional bodies seem to be regularly thwarted by veto, by talk of veto, or by some other lack of consensus."

It is something of a truism that technologies change the nature of conflict. What is significant, however, about developments of warfare in the current era is how a combination of technology and ideas about its lethal and destructive use at a level below "hot war" challenges both conventions in diplomacy and international law, not least regarding sovereignty.

The reality of this state of affairs is clear. A state of "cool" cyber war already exists with a number of state actors and proxies launching daily attacks, driving a cyber arms race that has seen western countries engaged in a not so virtual arms race. It is not only China that has been responsible. The US and Israel were behind the Stuxnet virus, which was able to take over and use the Iranian computer control systems to damage nuclear centrifuges, a strong indication of the potential for physical damage to industrial systems that such attacks are capable of inflicting across state boundaries.

If cyber warfare has heralded a new era of sabotage and espionage, the escalating use of unmanned drones flown by operators far away from the front lines raises similar concerns. What is not at issue is whether drones are inherently more or less moral than any other lethal weapons system. What is crucial under the laws of war is the intent – whether the target is justified, discriminate and whether the collateral risk to civilians proportionate.

If they do present an issue of special concern, as Michael Walzer, the ethicist and author of Just and Unjust Wars, has argued, it is not the rights or wrongs of targeted killing – something that has always taken place in war and proscriptions on its use in a state of conflict are governed by international humanitarian law.

Instead, he insists, "the difficulty" lies in the fact "the technology is so good that the criteria for using it are likely to be steadily relaxed", which he argues as already happened in Pakistan and Yemen. The problem, shared with the use of other new technologies of every kind in the Cool War, is that it makes different kinds of low-level conflict far too easy. Walzer is right. We should be worried. One of the key features of the "war on terror", a component of the Cool War, as critics have pointed out, is the way in which it has become open-ended.

While much has been written about why wars happen, it is worth considering why states seek to avoid conflict – because they are difficult and risky to prosecute and because the human and financial cost is high. It is an idea that was summed up by the US Confederate general Robert E Lee: "It is well that war is so terrible, lest we should grow too fond of it." But the tactics and strategies of the Cool War are attractive to policy-makers precisely because they are low cost – in the lives of the servicemen waging them and in political terms as well – and seem less dangerous than "real" war.

If there is a final feature of the Cool War, it is how much of it is being prosecuted at the very margins of accountability, either by secretive organisations such as the CIA, the Chinese People's Army or by proxies, without defined goals or a willingness to discuss how such campaigns affect questions as diverse as sovereignty and international conventions.

If there is some reason for optimism it is that the slide towards the Cool War has not gone unremarked. The legal issues that have been raised, the lack of transparency and challenges it poses have been raised by legislators and human rights campaigners. Indeed, the issue of the legality of drone warfare is being investigated by the UN. But the debate so far has been deeply fragmented. What is necessary is a proper discussion about how new technologies and new ways of conducting military operations impact on everything from human rights to borders and sovereignty in an era of global connectivity where a state's interests can be attacked from a distant computer screen.

The reality is that far from being low risk and low cost, the threatened new era of shadow wars, cyber warfare and unconstrained adventurism is truly dangerous. A continuing state of cool conflict without a front, without clear rules and without accountability, is a recipe for ever-rising tensions and the risk of real hot wars.