Britain might try to use its security and defence prowess as a bargaining chip in Brexit negotiations. But that strategy could backfire, with serious collateral damage.

The United Kingdom’s exit negotiations with the European Union have not yet officially begun, but it is already becoming clear that no policy area will remain unaffected by the breach between the EU and the UK – not even security and defense policy cooperation.

In fact, Prime Minister Theresa May considers British contributions to European security one of her strongest cards in the Brexit negotiations – but she is walking a tightrope between fostering goodwill in Europe and alienating Europeans by issuing hollow threats. For their part, many European governments are too quick to dismiss British security capabilities, prioritizing principles over pragmatism instead of looking for ways to keep Britain close.

The UK is one of only two credible military powers in Europe and has a permanent seat on the UN Security Council. London commands extremely effective intelligence services with substantial skill and know-how in the fight against terrorism and organized crime. And while the British military has been subjected to budget cuts in recent years, the global outlook of the British, their diplomatic network, and the professionalism and training of their military personnel all contribute to European security.

So how could the UK use its defense and security capabilities to win a favorable Brexit deal from the EU? Crude blackmail would not work and thankfully seems unlikely in any case. It is true that some Brexiteers are asking, in private and in public, why British troops should risk their lives for EU member states that want to impose a “punitive” Brexit deal. But May knows that any open threat for example, to withdraw troops from NATO rotations in Central and Eastern Europe if the Baltics block a tariff-free trade agreement between Britain and the EU-27 would not just be unhelpful, but would also lack credibility.

The Trump Card

Britain, unlike newly elected US President Donald Trump, knows that the value of collective defense and security is greater than the sum of its parts. During the EU referendum campaign, Brexiteers and Remainers alike stressed the enduring value of NATO as the bedrock of British security. And the UK government has a continuing interest in investing time and resources in Europe’s defense, not only to protect its own national interests but also to generate goodwill abroad – especially as Brexit negotiations unfold and demonstrate to other allies (not least the US) Britain’s enduring or ambition to be a global player. Almost immediately after the Brexit vote, Britain signaled its continuing international engagement at the July Warsaw summit, when it announced the deployment of 650 British troops to Estonia and Poland as part of a new deterrent force on NATO’s eastern flank.

Still, the UK government is well aware of the value of its military capabilities. In her Brexit speech at Lancaster House in January, May said she was optimistic that Britain and the EU would come to “the right agreement,” because the EU needed the UK as a partner in matters of security and defense. She stressed that Britain had led Europe “on the measures needed to keep our continent secure,” on implementing sanctions against Russia, working for peace and stability in the Balkans, and securing Europe’s external border. She reminded all EU countries that British intelligence services were “unique in Europe” and had saved countless lives, thwarting “very many terrorist plots” in countries across Europe.

May is right. The EU needs the UK’s capabilities – and Trump’s election has the potential to further strengthen the British negotiating position. Notwithstanding recent attempts by new US Secretary of Defense General James Mattis and others to reassure European allies, Trump’s “America First” nationalism and his skepticism of multilateral organizations calls into question the American security guarantees that Europe has been relying on for decades.

May wants to leverage the UK’s special relationship with the United States in conversations with other European leaders, by offering to act as a bridge between the US and the EU. On a visit to Washington, DC she managed to wrest a commitment to NATO from Trump, whereas in Brussels she conveyed Trump’s message that Europeans need to invest more in defense spending through NATO.

Most EU leaders agree with May’s message but disapprove of the messenger: They know that the Trump administration’s erratic approach to Europe and NATO is a real concern, but they find it difficult to accept May and her Brexit government’s help. They want to spend more money on defense for the EU’s sake, not because Trump or May request it. To make her offer more acceptable to Europeans, May should coordinate her next meeting with Trump and other EU leaders together.

Walking the Tightrope

With its embrace of the Trump administration, the UK government is attempting a difficult balancing act: Britain will appear more alien to the EU-27 the more it fails to criticize Trump on his most egregious policies. But if Britain uses its special relationship to promote European security and the crucial role the EU has played in consolidating a troublesome continent, it can earn European goodwill for the upcoming negotiations.

Trump’s election, and, more importantly, Europe’s unstable neighborhoods to the east and the south have spurred EU leaders to boost their support for European defense. France and Germany in particular have thrown their political weight behind a reform of the union’s Common Security and Defense Policy (CSDP). This presents a potential European vulnerability during Brexit negotiations: As long as the UK is still officially a member of the European Union, London also retains its veto on EU defense policy initiatives that require unanimity. For now, it seems unlikely that the UK would block the CSDP ambitions of the EU-27; the British government is well aware of how badly the EU would take such obstructionist behavior.

But many Britons are worried about the potential of EU defense policy duplicating and undermining NATO. In the months before the EU referendum, the old bogeyman of the EU army became a favored trope of Brexit campaigners. If the mood worsens significantly between the UK and the EU-27 over the course of Brexit negotiations, these concerns could take center stage once more, and May’s government could find itself pressured to disrupt EU defense initiatives.

Yet doing so would not be in Britain’s long-term interest. Once the UK’s exit has been negotiated, London will want to strike some form of association agreement on EU defense. The less obstructive Britain is now, the more it can ask for voting and operational planning privileges in the future.

Turning its contributions to the European security architecture into a bargaining chip, London risks undermining European goodwill. Playing the security card as an open threat would backfire, as it would be considered an assault on a core common interest and European values. Instead, London should make clearer how it aims to contribute to European security, prosperity, and stability once it has left the EU.

However, it is not just Britain that needs cordial post-Brexit relations. Some EU governments would be well-advised to take a more pragmatic stance on security and defense policy cooperation with the UK. The EU’s negotiating strategy is currently guided by one basic principle: Britain cannot be better off outside the EU than as a member. This is aimed at undermining euroskeptic movements in other member states. Following this rationale, many EU countries are quick to dismiss privileged association formats for the UK post-Brexit, for example on CSDP operational planning or European Defense Agency projects.

But Europe cannot afford to lose British capabilities at a time when the European security situation has deteriorated significantly. Close cooperation between Britain and the EU in the area of ​​security and defense, guided strictly by shared interests, would be a good thing for both sides.

N.B. This article draws on the findings of an extensive Center for European Reform (CER) study conducted

with Christian Odendahl: “Berlin to the Rescue – A Closer Look at Germany’s Position on Brexit”

