Military confrontations have re-entered western Europeans’ collective imagination. Military capability consists of not only an intricate network of hard power, but also softer elements such as alliances, readiness, and the ability to act – and can be deeply affected by technological developments.

Senior Policy Fellow

Military power is notoriously hard to measure, and yet it is one of the areas of state power in which measurements are the most prevalent and sought after. Few things are as crucial to know before a military confrontation as the opponent’s military strength. For many years, military, or hard, power was widely considered the primary source of a state’s power. However, towards the end of the cold war, economic power took over. A prevalent narrative about the ‘end of history’, combined with a decrease in military confrontations, led to a belief – or hope – that wars would largely be a thing of the past. This belief was illustrated most clearly by US leaders’ fear in the 1980s that Japan – a country that had a pacifist constitution and was unable to legally send military forces abroad – could overtake the United States due to the rapid growth of the Japanese economy.

But military power is back. Military confrontations, including those between great powers, have re-entered western Europeans’ collective imagination. Global military expenditure has risen steadily in the last two decades. And, last year, according to the Stockholm International Peace Research Institute, it reached almost $2 trillion. US military expenditure alone accounted for an estimated 39 per cent of this.

Judging by the data on military expenditure in Map 1, it seems easy to identify the key military powers of this century. The US outspends its competitors and partners to a significant degree. China’s military expenditure has rapidly increased in recent years, and now stands at $193 billion, or 1.3 per cent of GDP. Smaller states such as Afghanistan, Saudi Arabia, and Israel spend a relatively large share of their GDP on defence – due to ongoing conflicts, heightened threat perceptions, or a desire to gain regional influence.

Map 1Download image

The nuclear powers: Number of nuclear warheads

The world’s key military players also tend to be members of one of the most exclusive global clubs: nuclear-armed states. As of 2021, nine states have nuclear weapons (Israel has a policy of deliberate ambiguity about its nuclear capabilities). More than 90 per cent of the roughly 13,080 nuclear warheads worldwide belong to the US or Russia (see: Map 2). Five states – the US, Russia, the United Kingdom, France, and China – are members of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT). This means that they have promised to “pursue negotiations in good faith on effective measures relating to […] nuclear disarmament”. But the continued existence of nuclear weapons, despite the NPT and the more recent Treaty on the Prohibition of Nuclear Weapons, underlines an important element of military power: deterrence, or the capacity to demonstrate so much capability that a potential adversary is deterred from attacking. Nuclear weapons are generally understood to be procured to not be used, as weapons of last resort that have little tactical impact but provide such deterrence.

Map 2Download image

The nuclear powers
Number of nuclear warheads
    * In early 2021, the United Kingdom announced an increase in the cap on its nuclear stockpile from 225 to 260 warheads.

    At the start of 2021, nine states – the United States, Russia, the United Kingdom, France, China, India, Pakistan, Israel, and North Korea – had approximately 13,080 nuclear weapons, of which 3,825 were deployed with operational forces. Approximately 2,000 of these are kept in a state of high operational alert.

    Source: SIPRI (2021). SIPRI Yearbook 2021: Armaments, Disarmaments and International Security. Oxford University Press

    In light of Maps 1 and 2, one might assume that the ranking of the world’s military powers is rather obvious – and, with the exception of China, fundamentally similar to that of recent decades. However, in the US and other Western countries, alarm bells have been ringing for a while. For example, the US National Security Commission on Artificial Intelligence argues that “America is not prepared to defend or compete in the AI era. This is the tough reality we must face.” Some Western states fear that emerging technologies could empower new actors, including smaller states or even non-state actors, to inflict significant costs on established powers. And, even though kinetic military confrontations might become more common again, the more immediate concerns are hybrid operations such as cyber-attacks, the weaponisation of migrants, and disinformation campaigns – all challenges against which tanks, aircraft, or nuclear weapons are largely useless. Therefore, in the twenty-first century, military strength will be determined by not just hard power but also a state’s ability to develop and use new technologies, react quickly to challenges and build resilience against them, and draw on support from its partners and allies.

    The role of new technology

    There have been moments in history when warfare changed because of the introduction and innovative use of a new military technology. The crossbow and gunpowder, the tank and nuclear weapons – when militaries first adopted and used such technologies in novel ways, this sometimes had a fundamental impact on how they fought wars, organised their forces, and developed strategies. These moments are called ‘revolutions in military affairs’. And enacting such a revolution before the opponent does so is the holy grail for militaries around the world.

    Today, there are several new technologies that will become significant elements of military power. Unmanned aerial vehicles, or drones, have received a lot of attention in recent years. Their development, which dates back to the early 2000s, has played an important role in the ‘war on terror’ fought by Western militaries. More recently, drones – especially armed drones – have proliferated to the point that they are now on battlefields around the world. As the use of drones in the 2020 conflict between Armenia and Azerbaijan in Nagorno-Karabakh demonstrated, there is a role for drones beyond asymmetric wars, such as in confrontations between states. While today’s generation of drones is unlikely to be the decisive factor in a full-blown military conflict, they can markedly boost the air power of states (or, indeed, non-state actors’ airborne capabilities). Several states, such as Turkey and China, have in the last few years invested significant resources in the creation of domestic drone industries. As Map 3 illustrates, many countries now have military drones – a dozen or more of them armed drones. Differences in drone arsenals can be substantial enough to change traditional balances of power: Turkey now has an estimated 140 armed drones – compared to the UK’s ten, France’s 12, and Germany’s none (despite a long-running debate about whether to lease five armed drones for its air force).

    Map 3Download image

    Military drones: Countries with a military drone inventory and counter-drone technology systems

    Accompanying the rise of drones is a rise in counter-drone systems. As Map 3 shows, a variety of counter-drone systems are being used, developed, and tested. Broadly speaking, there are three ways to down a drone – kinetically, electronically, and by interception. The first involves shooting drones down with bullets, rockets, or similar munitions. The second – electronic solutions – is currently the most promising. It requires the capability to jam or interrupt the signal between the drone and its operator. A more advanced version of this approach is to hack into the drone and take command of it. Lastly, there are several ways to intercept drones. For instance, one can use drones to fight other drones, or can down them with the kind of shoulder-mounted net-throwers that have appeared at several high-level political meetings this year (though these latter capabilities are more relevant to the civilian context than the military one). While anti-drone systems do not directly translate into military power, the inability to defend oneself against drone attacks can have devastating consequences and create significant vulnerabilities. But, for now, states have not found any one capability that can counter most drones, let alone all of them. In this environment, even relatively small and basic drones can pose a significant threat.

    Cyber is another area widely expected to upend traditional power balances, with the proverbial teenager in their bedroom able to hack state institutions. Although such attacks are possible, most substantial cyber-power still lies with states, specifically those willing to invest resources in the requisite capabilities. The Belfer National Cyber Power Index measures 30 countries’ cyber-capabilities. It ranks the top ten cyber-powers across the seven objectives it measures in the following order: the US, China, the UK, Russia, the Netherlands, France, Germany, Canada, Japan, and Australia. However, as Map 4 shows, states’ performance varies a great deal across these indicators. For example, China, France, and even the Netherlands rank above the US on defensive capabilities, pointing not only to the complexity of such capabilities but also to how they might empower smaller states instead of the usual suspects.

    Map 4Download image

    Top 5 ranking by selected component
    Offence (Power to destroy or disable an adversary’s infrastructure and capabilities)Defence (Power to strengthen and enhance national cyber defences)
    1United StatesChina
    2United KingdomFrance
    4ChinaUnited States
    Source: Voo, J., Irfan, H., Jones, S., DeSombre, W., Cassidy, D. and Schwarzenbach, A.. (2020). National Cyber Power Index, September 2020

    With regard to space technologies, however, the old dictum of ‘quantity is a quality of its own’ still largely holds true. Many actors are building up their space capabilities, which includes satellites and earth-based space commands (see: Map 5). A country such as Luxembourg may have a satellite, or Peru a space command, but larger, more established military actors – such as the US, Russia, and China – still dominate this area through sheer numbers of satellites.

    Map 5Download image

    Another promising but hard-to-measure area of military technological development is artificial intelligence (AI), which can enable and support activities in everything from logistics to autonomous weapons, cyber-warfare, and disinformation. These capabilities include offensive and defensive front-line and support systems.

    Military experts agree that states will increasingly use AI in the military realm, and that this will have important implications. However, their assessments of what these implications will be run from maximalist statements that AI may “alter the immutable nature of war”, or that AI changes “the psychological essence of strategic affairs”, to less extreme views that focus on more specific and limited changes in weapons technology.

    In recent years, the maximalist reading has taken hold in US circles in particular. The US National Security Commission on AI argues that the US “will not be able to defend against AI-enabled threats without ubiquitous AI capabilities and new warfighting paradigms”.

    But it is difficult to make predictions about where AI will have the biggest impact on military systems and operations. And, for now, reliably measuring a state’s military AI capabilities is almost an impossible task. Artificial intelligence is still in development – with companies inventing new approaches, and making important improvements, to it. Moreover, most of the most ground-breaking work on AI occurs in the civilian realm.

    Most importantly, it is difficult to make predictions about any technology’s impact on warfare. This is due to the fact that what matters for a military technology’s impact is not just the technology but how it is used. For a new technology to have a significant impact, users need to come up with novel ways of using it, along with doctrines for doing so. For example, tanks were on the battlefield in 1916. But they did not show their military potential until the second world war, during which the Wehrmacht’s Blitzkrieg doctrine combined the use of radios with a novel way of deploying tanks as independent units, allowing Germany to break through French defences in a matter of days. It is still unclear what new doctrines, organisational changes, and training regimes will develop in relation to military AI and other emerging technologies – or what impact they will have.

    In addition to such uncertainties, absolute military capabilities are only relevant up to a point. The kinds of military systems, training, and doctrines that are needed also depend on the type of military operations they expect to be involved in. An all-out inter-state war between peer competitors requires different capabilities to a smaller intervention or an asymmetric conflict.

    A particularly difficult-to-measure indirect military capability is proxy forces and private military actors, which some states rely on for everything from logistical support for their troops to secret military operations. When the US drew down its forces in Afghanistan in early 2021, the US Department of Defence confirmed that more than 18,000 private contractors remained in the country. Russia’s Wagner Group has become increasingly active in countries ranging from Syria and Ukraine to, more recently, Mali. Media reports have uncovered China’s fledgling private security industry. Unfortunately, there is no reliable publicly available data on the number and impact of these groups. And it is difficult to compare their activities across different countries: some groups only provide legal and largely non-military services in conflict zones, while others are de facto paramilitary actors that do states’ dirty work with a certain level of deniability.

    A state’s military capabilities, particularly those for operations beyond its territory, depend substantially on its capacity to project power. This capacity can come from platforms such as aircraft carriers, long-range missiles, and over-the-horizon drone capabilities. But permanent bases in overseas territories or other countries’ territories can be especially valuable for power projection. Such bases allow states to make much faster deployments of troops and personnel to nearby crises. As Map 6 shows, only a handful of countries have overseas bases – but they have a lot of them. France and the UK have many overseas territories in former colonies, while the US has such territories and an extensive alliance system that includes several agreements to station its troops abroad. Elements of the United States’ overseas presence are also remnants of the post-war order, with Japan and Germany home to the largest American military installations outside the US mainland. In 2016 the People’s Liberation Army (PLA) began constructing its first overseas base, in Djibouti. This small country on the Horn of Africa is also home to US and French military installations, as well as the first full-scale overseas base of Japan’s Self-Defence Forces.

    Map 6Download image

    Overseas bases

    While states can benefit from stationing and training troops abroad (see: Map 7), there is no substitute for real combat experience: one can assume that states that have deployed troops in combat in recent years would perform better in military operations than those that have not done so for a long time. For many Western – especially European – militaries, the wars in Afghanistan and Iraq were an important driver of military modernisation. China, in contrast, last fought a war in 1979 – which might put into question the PLA’s fighting ability. Of course, if a deployment becomes too extensive, it can be a drain on, rather than a boost to, a military’s war-fighting capabilities and financial resources (considerations that were part of the reason for the US withdrawal from Afghanistan earlier this year).

    Map 7Download image

    Military deployments abroad

    A strong, independent defence industry likely helps states adapt to military developments, be they technological or political. A national defence industry can allow states to quickly scale up production of military systems, if needed – and to do so without support from others. Map 8 shows that the US has a significant advantage here, with a substantial number of the world’s largest arms producers located there. But France and the UK also punch above their weight in this field, with eight and six major arms producers located in the two countries respectively.

    Map 8Download image

    World’s largest arms-producing and military services companies: Number of companies in SIPRI Top 100 by country

    Yet, while independence can be beneficial to a state’s military capability, support from others can also be crucial. Alliances, particularly those with mutual defence clauses such as NATO’s Article 5 or the European Union’s Article 42.7, significantly boost a state’s military power. This is because that state no longer needs to rely only on its own military capabilities, as it can receive support from those of its allies.

    Therefore, military capability partly consists of an intricate network of hard power, which one can measure with indicators such as expenditure and numbers of tanks and military bases. But it also includes softer elements such as alliances, readiness, and the ability to act. And efforts to assess states’ military capabilities are complicated by the impact of technological developments, a constant companion to military power. As many armed forces have learnt the hard way, no measurement can substitute for real experience.