Trump is coming, so we need a UK-EU security agreement fast

The invasion also prompted a rapprochement between the United Kingdom and the European Union after the difficulties of the Brexit negotiations. Britain’s decisive response to the crisis reminded Europeans of the UK’s indispensability to European security, while the EU’s emerging strategic role made Britain’s post-Brexit policy of “splendid isolation” appear foolhardy.

Cooperation emerged gradually and in an ad hoc manner, but this did not diminish its importance. High-level talks took place between both sides and London signed on to EU sanctions packages, sent observers to the EU’s military clearing-house cell in Brussels, and signed up to the Military Mobility PESCO project.

Yet ideological opposition among pro-Brexit Conservatives to formalised security cooperation prevented the adoption of more formalised arrangements, even after Rishi Sunak’s negotiation on the Windsor Framework, which removed the most significant and ongoing problem in the relationship.

Labour’s quest for a security agreement

The election of a Labour government in July 2024 changed this. Prior to election, David Lammy had pledged the party would seek a security agreement with the EU to “take back control” and Keir Starmer followed up in his first weeks in office with exploratory talks in Brussels, a security pact with Germany, and an agreement with the EU on six-monthly summits beginning in 2025 to discuss foreign policy and security issues.

Labour’s rationale for seeking a security agreement is part practical and part political. Practically, a structured format would enable deeper cooperation, build trust, and ring-fence cooperation from short-term political whims on either side. Politically, an agreement would allow Labour to build bridges with Europe in an area where the public is on-side and the cost to UK sovereignty minimal.

Longer-term ambitions probably feature in Labour’s strategy. Many on the UK side – among Tories and Labour – have hoped that an agreement on security and defence could contribute to improved relations in other areas and perhaps even greater access to the European internal market.

But a security agreement is not the way to build back to Europe. The EU has been clear about its own ‘red lines’ and has no intention of departing from these. Not only is there no desire to re-open the TCA, there remains a fear that offering Britain anything that upends the existing balance of rights and obligations would bring about the end of the European project.

The Trump factor

The election of Donald Trump to the White House for a second term presents a serious challenge to the coalition of Western and European countries supporting Ukraine. Trump’s desire for a negotiated settlement is well known, as is his scepticism of the US contribution to NATO. Given America’s as the largest funder, coalition leader and ultimate guarantor of European defence, Trump’s election spells trouble for Europe.

It also coincides with increasing war fatigue on the continent, with higher energy costs and increased national defence spending taking their toll on public opinion, weariness of the intractability of the conflict creeping in, and populist governments of all stripes seeking to capitalise on popular discontent.

Trump’s impact on European responses hangs in the balance. On the one hand it increases the costs of backing Kyiv while reducing the chances of outright success, a dispiriting prospect for government and citizens alike. For this reason, it is thought Trump’s victory might further contribute to the fracturing of the European coalition, especially on behalf of European populists.

On the other hand, his election may have a galvanising effect. By placing responsibility for their security more squarely with the Europeans, the Trump Presidency may bring about enhanced cooperation, greater ownership of the conflict, and new structures and processes.

While Trump has his fans in Europe, for populist movements and governments on the continent it is their security at stake – their moment of existential crisis. Trump’s election calls their bluff, and it remains to be seen how many are willing to sell out Ukraine – and their own future security – when there is no fallback.

History would suggest that the latter of these two scenarios is the most likely. Intra-European solidarity has been at its highest at moments where American security commitments are called into doubt, and these have brought about moves towards greater European security and defence cooperation. 

The impact on the UK

Britain, too, becomes more Europhile when confronted with a less predictable US commitment. Think Ted Heath in the early 1970s and Tony Blair in the late 1990s. Even Theresa May sought to keep the UK connected to evolving EU security initiatives after Brexit in part because of concerns over Trump’s actions in his first Presidency. This makes sense, because Britain needs Europe more – and vice versa – when American support is in doubt.

Trump’s election makes a security agreement with the EU even more vital. Through the improved coordination and engagement such an agreement would bring, both sides could achieve significant efficiencies and cost-savings that could make European resources go further while building up trust between allies and helping maintain a coherent European narrative.

Increased coordination would also help bring about a united European front when lobbying the US leadership, not only precluding individual nations from falling into line with the US position, but also capitalising on the UK’s ‘special relationship’ to convey broader concerns. And should this diplomatic effort fail, there will exist a ready platform for discussing European initiatives to address any shortfall or defence gap.

With Trump in the background, agreement may be easier to reach on an outcome that works for both sides, given the severity of the stakes. This does not mean the UK will be able to rethink Brexit-era red lines or obtain a broader agreement, but it does mean the UK might be afforded greater influence over decisions and access to EU defence initiatives unavailable to other third countries.

With Trump in the White House for the next four years and the Western alliance thrown into chaos, now is the time more than ever for Britain and the EU to come around the table and agree workable arrangements for guaranteeing the security of the continent – and its neighbours – in America’s absence. 

Ben Martill’s report on UK EU security for the Independent Commission on UK EU Relations can be found here.