The Strategic Defence Review (SDR), published in June 2025, explained that His Majesty’s (HM) Government would adopt a ‘NATO First’ approach in order to secure the Euro-Atlantic in the face of Russian revanchism and the potential adjustment of regional priorities by the United States (US).
Such an approach fits the perspective that the 32 member-strong North Atlantic Treaty Organisation (NATO) is a key strategic advantage which the United Kingdom (UK) has. After all, strategic advantage refers to how a country can catalyse the resources and tools which it has at its disposal to broaden a strategic impact, with alliances offering a multiplier effect by incorporating like-minded states into that country’s activities. To put matters more concretely, Britain might already deter nuclear strikes by Russia thanks to its own nuclear arsenal, but it can strengthen deterrence against Russia by covering other possible forms of attack through close political coordination and defence collaboration with other NATO members.
But is there a limit to the strategic advantage that treaty-based alliances like NATO could offer? At what point might alliances become a source of disadvantage, whereby they weaken deterrence? The answer in brief is that military alliances can become strategically disadvantageous, but thankfully – and perhaps paradoxically – the exercise of national sovereignty and the availability of so-called minilateral options can limit those shortcomings.
The first potential source of strategic disadvantage is that nothing about military alliances is automatic. As formal mechanisms that serve to cooperate on defence policy, military alliances are only as good as their membership. If, for whatever reason, allies fail to develop the capabilities necessary for conducting military operations effectively, then the alliance itself will lose credibility, exposing it to opportunism on the part of the adversary that is supposed to be deterred. Alternatively, if allies disagree too much about what is to be done in a specific crisis situation, the alliance risks paralysis, and can cede strategic initiative to the adversary.
The second is that the military and political commitments which underpin an alliance could engender misbehaviour among certain allies. Thinking that the alliance will shield them no matter what, some states might become much more aggressive towards the adversary than they would otherwise be, creating a spiral of insecurity which produces conflict when the very purpose of the alliance is to prevent it. If the result is not an emboldening, it could instead be complacency, with allies feeling so secure that investing in their own defence seems superfluous to them.
From the UK’s perspective, the possible downsides of a military alliance such as NATO are easy to overstate for two limiting factors: political sovereignty and the availability of minilateral or bilateral workarounds.
These shortcomings can be serious. In the last decade, dual concerns about free (or easy) riding on the US and allied overconfidence have intensified in American national security discourse, so much so that they could be the basis for the Trump administration to go about a major restructuring of US force posture around the world. This in part explains why the SDR emphasises the value of NATO as much as it does.
From the UK’s perspective, the possible downsides of a military alliance such as NATO are easy to overstate for two limiting factors: political sovereignty and the availability of minilateral or bilateral workarounds.
Political sovereignty is a core value which forms the foundation of NATO. All alliance decisions must be based on consensus, and all countries can determine for themselves how to gauge a particular crisis and what contributions they wish to make for addressing it. At first glance, this need for consensus seems like a major weakness: any invocation of Article Five implicates nothing, and decision making could be slow. However, it discourages adventurism, especially among NATO’s weaker members, because no rational ally should be confident that it will receive universal support for any bold initiative it takes.
Political sovereignty also is better for cohesion, as no country would be loyal to an alliance to which they are captive, and in which organisational decisions could be made directly at their expense. The Warsaw Pact is illustrative of this – its members chose to disband the Soviet-dominated alliance soon after getting the chance to do so as post-communist countries.
Although NATO still offers a cohesive multilateral framework for European security, more of its members are pursuing partnerships in alternative but complementary security formats.
The second limiting factor derives itself from the first. Members can still develop minilateral or even bilateral workarounds if they perceive that the alliance might not be conducive for a specific purpose or task. Even if no specific commitment might be triggered, certain initiatives – such as forward military deployments, out-of-area operations or security cooperation with non-allies, for example – undertaken by some allies could be deemed undesirable or not worthwhile by others.
Minilateral groupings have this flavour. Although NATO still offers a cohesive multilateral framework for European security, more of its members are pursuing partnerships in alternative but complementary security formats. This allows them to pursue projects which they view as priorities, but which may be prone to paralysis if worked through the entire NATO membership.
Many examples abound. The Bucharest Nine comprises countries that joined NATO since the end of the Cold War, with the purpose of coordinating security and defence policies, often ahead of major alliance-level meetings. Britain took the lead in setting up the Joint Expeditionary Force (JEF), a group of Nordic and Baltic countries which contribute maritime and expeditionary capabilities intended to secure Northern Europe. It also established the trilateral initiative with Poland and Ukraine to advance cooperation across multiple policy domains aimed at enhancing European security.
Indeed, in the general thicket of minilateral and multilateral forms of cooperation that makes up the European security architecture, bilateralism remains essential. Most American troop deployments are handled on a bilateral basis, and agreements are struck with host countries regarding the terms and conditions relating to the activities and support of forward-based personnel and capabilities.
Military alliances can be an integral source of strategic advantage, but ‘more military alliance’ does not necessarily translate to ‘more strategic advantage’. These security arrangements can have their downsides, especially if members are negligent in pulling their weight, or see in their received commitments an opportunity to be reckless abroad. Thankfully, for a leading power such as the UK, sovereignty and minilateralism with like-minded partners can attenuate those drawbacks.
Dr Alexander Lanoszka is an International Fellow at the Council of Geostrategy and associate professor at the University of Waterloo in Canada. His latest book is Military Alliances in the Twenty-First Century, published by Polity in 2022.
This article is part of the Council on Geostrategy’s Strategic Advantage Cell.
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I suppose much rests on the continued worth of NATO. If the underpinning value is US participation, which demonstrably it is, and the US continue their reorientation towards China, then NATO loses its worth and participant nations should invest their energies/resources/treasure in other more aligned alliances - there is nothing wrong with this as long as they are able to cohere across the mini-alliances into something meaningful. Interoperability is going to be the key capability for that to succeed, and I fear Europe has a long way to go on that in short order.