THE EUROPEAN – SECURITY AND DEFENCE UNION
There are many ways to raise the cost of an attack for an aggressor
Deterrence in the 21st century: necessary, but not sufficient
by Michael Rühle, Head of the Hybrid Challenges and Energy Security Section, NATO’s Emerging Security Challenges Division, Brussels
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or over seven decades, deterrence has been a key concept of western defence and strategic thinking. The reason for this prominence is not difficult to fathom. Deterrence is congenial to democracies. As Lawrence Freedman, one of the most prominent analysts of deterrence, observed, when a state adopts a deterrence stra tegy “it signals that it does not seek a fight but still considers some interests to be so vital that they are worth fighting for. It implies a defensive intent without weakness. It seeks to prevent aggression while being non-aggressive. It sustains rather than disrupts the status quo.”
tried not to overstep certain “red lines” or push the other side into a corner. In other words, it was a game for high stakes, but it was also a game that followed certain unwritten rules. Traditional (mostly nuclear) deterrence is still an important part of taming interstate relations, even if the emergence of new nuclear players, such as North Korea, and new technologies, such as hypersonic missiles, have made the game more difficult.
requires investment in cyber “Resilience defence, in the protection of critical energy
infrastructure, and in public education on how to deal with fake news on social media.”
The principle of deterrence It is therefore not surprising that many scholars are now trying to apply deterrence to new threats, such as cyber, disinformation, election interference, or “hybrid” combinations of such activities. If deterrence worked in the Cold War, when the threat of nuclear annihilation reminded all sides to act with caution and restraint, so the thinking goes, perhaps it can also be made to work against less visible, non-kinetic threats. If only it were so easy. Deterrence in the Cold War worked because the interests at stake were existential and, hence, threats of using force – even nuclear force – to defend these interests were credible. Moreover, both sides at least tacitly acknowledged – and largely respected – each other’s spheres of interest. Finally, while the Cold War saw immense political and economic competition between East and West, both sides
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Still, the major challenge for traditional inter-state deterrence is less the question of whether it still works, but rather whether its most important means – nuclear weapons – are still morally acceptable. The Treaty on the Prohibition of Nuclear Weapons, or Ban Treaty, which has now entered into force, seeks to de-legitimise nuclear weapons and thus create political and social pressure for their ultimate abolition. However, it is unlikely that the Ban Treaty will achieve its goal, given that no nuclear power or their allies have signed it. Hence, nuclear deterrence will be around for a long time to come.
Does deterrence apply to new threats? The real challenge for the concept of deterrence today is whether it can also apply to non-kinetic, non-existential threats. Employing the term “deterrence” in this context may
