The United Kingdom’s exit from the European Union will mark one of the most significant shifts in European and transatlantic geopolitics since the fall of the Berlin Wall. It will also take place at a time when the United States’ traditional transatlantic outlook has changed under Donald Trump’s administration. How might foreign policy cooperation between the United Kingdom, the EU, and the United States adapt to this new context? What new mechanisms for cooperation might Washington, London, Paris, and Berlin—as the four main transatlantic powers—consider?

British Foreign Policy Between 1989 and 2016

Since the end of the Cold War, British foreign policy has been based broadly on three strategic pillars. The first is Atlanticism and transatlantic unity. London has been aligned with Washington on major international security issues; supported an internationalist and values-based U.S. foreign policy; and positioned itself as a transatlantic bridge, explaining European views and policies to the United States (and vice versa).

The second pillar is leadership in Europe. The United Kingdom has shaped the development of both the European continent—for instance, in the political outcomes of the post communist upheaval in the Balkans—and the EU. London championed two of the EU’s biggest geopolitical developments: the single market and the post-1989 enlargement into Central and Eastern Europe. Since 1992, the United Kingdom has also played a leading role shaping the EU’s Common Foreign and Security Policy (CFSP), which it often has used to secure pan-European support for its foreign policy objectives (for example, on Russia). In recent years, the UK has also worked with France and Germany in the E3 format.

David Whineray
David Whineray is a nonresident fellow in the Europe Program at the Carnegie Endowment for International Peace in Washington, DC.
More >

The third pillar is multilateralism. As a medium-sized power with global equities, successive British governments have viewed an effective rules-based international order as important in advancing British interests. In line with this, the United Kingdom has played an active role at the United Nations—including utilizing its status as one of the five permanent members of the UN Security Council (or P5)—as well as in other international and regional organizations such as NATO, the Organization for the Prohibition of Chemical Weapons, and the Organization for Security and Cooperation in Europe.

Changes to This Approach

Three geopolitical shifts are under way that may now require an adjustment to how the United Kingdom, the United States, and the EU engage with each other on foreign policy.

First, Brexit naturally reduces Britain’s influence over the EU and over CFSP positions. The United Kingdom will remain a major European economic, political, and military power with considerable influence in its own backyard. However, it will be outside the room when the EU makes decisions.

Second, multilateralism and the rules-based international order are being challenged. From the East, there is Russian revanchism and growing Chinese assertiveness. Within the West, the Trump administration, unlike its Democratic and Republican predecessors, sometimes sees the current rules-based international order as a restraint on, rather than an enabler of, U.S. power.

Third, U.S. foreign policy more widely under the Trump administration has broken away from the post-1945 bipartisan Beltway consensus and become more nationalistic, transactional, and mercantile—with increased skepticism toward the EU and the traditional transatlantic alliance. In the foreign policy sphere, the Trump administration’s withdrawal from the Iran nuclear agreement (Joint Comprehensive Plan of Action, or JCPOA) was particularly significant as the first time in the last few decades that a U.S. administration has adopted a policy on a major international security issue without any European support.

Many Things Remain the Same

This changing context should not be overplayed. Constants remain. Regardless of whether it is in or out of the EU, the United Kingdom is a leading European power. London’s “Global Britain” agenda indicates the United Kingdom’s ambition to play a leading international role after Brexit. On some foreign policy dossiers, such as the Persian Gulf and North Korea, the EU has only a limited role and so any impact of Brexit on foreign policy cooperation will also be minimal. Despite recent criticisms by the White House of various European countries, overall U.S. cooperation with both Britain and Europe remains strong in important areas, such as in tackling chemical weapons. And transatlantic tensions have been high before, including under the Ronald Reagan and George W. Bush administrations. A future U.S. administration, whether Republican or Democrat, could revert to a more traditional global and transatlantic outlook (although not necessarily).

However, it also would be wrong to ignore the geopolitical impacts of Brexit and a changed U.S. transatlantic outlook. UK-EU and U.S.-EU relations are now different from the period before 2016. The Atlantic and the English Channel are a bit wider. For London, the traditional playbook on major foreign policy issues—align with Washington, lead an EU response—is now no longer always the one that is followed. For Brussels, Brexit means the EU will lose a nuclear power and P5 member. CFSP positions, historically driven by London and Paris, will become more French in orientation and may no longer be truly pan-European. For Washington, Brexit will mean that the United States no longer has its closest, most influential European ally around the EU table. Washington will have to work more with other EU member states to influence CFSP.

Adapting Transatlantic Cooperation to This Changing Context

As well as working more closely with the United States, the British government has publicly made clear that after it leaves the EU it also wants to continue to work closely with both Brussels and major European powers, especially France and Germany, on foreign policy. The EU, France, and Germany have said that they want to do likewise with the United Kingdom. The Trump administration has said that it wants to work with both Britain and the other major European countries on foreign affairs. So how should all this happen? How might London, Brussels, Paris, Berlin, and Washington evolve and adapt their foreign policy engagement, and work differently with each other, in this new context? What new agreements and mechanisms could be in their mutual interests to consider? Below are four possible ideas (in no particular order) that are in line with the policies of the current administrations/governments in those capitals (this essay is nonpolitical).

First, intensify bilateral foreign policy engagement. As CFSP has developed since 1992, some foreign policy cooperation between EU member states has been taken forward through Brussels. After Brexit, the United Kingdom and the EU27 may want to step up their bilateral foreign policy interaction with each other to ensure the overall level and intensity of engagement between them does not drop off. These efforts would be especially important between London and Paris/Berlin. Possible new mechanisms to consider could include new bilateral summits, dialogues, and agreements. The U.S.-Australian annual 2+2 meeting of foreign and defense ministers is an interesting model. The United Kingdom has already publicly announced that it is increasing its diplomatic presence in European capitals and that it has agreed new foreign policy agreements with both France and Germany. In terms of enhancing transatlantic relations, the United States and individual European countries might look at enhancing their bilateral structures too.

Second, make more use of other international formats and groupings of countries. Once Britain is outside of CFSP, an alternative way to coordinate action and agree on common foreign policy positions among Paris, Berlin, London, and Brussels might be for them to meet in other, smaller groupings. It could also be worth sometimes involving the United States in order to advance transatlantic cooperation. The E3, P3, and E3+U.S. (or European Quad) are the most influential groups. There could also be value in addressing more foreign policy within the Group of 7 (G7) format as well given its transatlantic composition. For example, the annual meeting of G7 foreign ministers could be supplemented with more regular meetings of senior officials. A new G7 version of a political and security committee could even be considered, perhaps meeting quarterly to agree on G7 positions or statements.

The use of small groups could advance U.S., British, French, and German interests. For Britain, being at the center of a network of these groups could be a way for it to exert influence on European foreign policy outside of CFSP. For the Trump administration, the Quad could provide a way for it to engage collectively with the three major European powers away from more formal, larger, and multilateral structures that it dislikes. For France and Germany, the E3 could provide an additional, more agile mechanism to CFSP to agree on quick European positions in response to international crises.

Some of these trends are already happening. In June 2019, Britain, France, Germany, and Spain issued a joint statement on Israeli actions against Palestinian buildings in Wadi al-Hummus. In August 2019, the E3 issued a joint statement on the South China Sea. On August 30, E3 foreign ministers—along with the EU high representative for foreign affairs—met to discuss Iran. In the wake of the poisonings of two Russian citizens in the British city of Salisbury in March 2018, E3 and U.S. leaders issued a statement. U.S. National Security Adviser John Bolton also recently tweeted that he met E3 national security advisers collectively. There also could be value in meetings of Quad foreign ministers. The E3 could even consider looking at the value of a joint compact setting out areas for cooperation.

Third, consider a new, collaborative post-Brexit UK-EU relationship on foreign policy. After Britain leaves the EU, it may still want to sometimes work closely with Brussels on foreign policy issues where the EU plays a major role—such as on Russia and the Balkans. Similarly, the EU may still want to work closely with the United Kingdom after Brexit on issues where Britain is a major player, such as in Yemen and Syria. There could also be other occasions, or crises, when both the EU and Britain may decide that they want to demonstrate (for example, to Moscow or Beijing) that their positions are closely aligned.

The EU and the United Kingdom could consider a future foreign policy relationship that enables such close engagement when desired. Various mechanisms could be possible. France’s Emmanuel Macron has suggested the idea of a new European Security Council that would include the United Kingdom. Another possible option could be for the UK to be invited to attend a session of the EU Foreign Affairs Council, as John Kerry did when he was U.S. secretary of state. Britain and the EU could even consider issuing a joint statement in an exceptional circumstance, for example in response to a country’s use of chemical weapons.

Fourth, the UK, France, Germany, and the United States could further intensify their cooperation in international organizations. The United Kingdom has made clear that support for multilateralism will be central to its post-Brexit foreign policy. Its recent announcements on G7 climate change commitments and deploying UK troops to the UN operation in Mali demonstrate this approach. In the context of U.S. skepticism toward multilateralism, French and German interests lie in supporting this British outlook. Other academics have argued that the E3 also need to work more closely together to protect the rules-based international order given Washington’s outlook on multilateralism. It will be important that they work with the United States, too. Like The Doors without Jim Morrison, the rules-based international order is not the same without the lead singer.

Some More Strategic Questions for Future Cooperation

Finally, at a more strategic level, after it leaves the EU, the UK will want to consider the overall geopolitical positioning it wants to adopt on foreign affairs between the United States and the EU. In short, does the UK want to align more closely with the United States on foreign policy after Brexit? Does it see its national interests and values as remaining aligned with the European mainstream? Or does it want to adopt a policy of strategic equidistance between the United States and the EU? Under Theresa May’s government, London was seen as being more aligned with the EU than with the United States on transatlantic differences, such as on the JCPOA, trade, climate change, the status of Jerusalem, and China. Washington and European capitals will look closely at whether this Euro-Atlantic posture continues, or changes, under Prime Minister Boris Johnson.

Within the European arena, the United Kingdom may also want to consider its strategic post-Brexit approach to foreign policy issues (such as the Balkans) where EU and British objectives are aligned but where Brussels plays a bigger international role. Will the UK want to play a supportive role to the EU on these files and focus its diplomatic capital on other dossiers where it has more influence—for example, in South Asia? Or will the United Kingdom decide to play a leading role across the foreign policy waterfront? The EU will face similar questions. On those issues where the United Kingdom has driven EU foreign policy as a member state (for example, in the case of Burma), will Brussels decide to support British leadership after Brexit? Or will the EU want to develop a new (alternative) role for itself?

The answers to these questions likely will depend to an extent on how the United Kingdom leaves the EU after the October 31 deadline—and whether the United States, the United Kingdom, the EU, France, and Germany decide to adopt collaborative, or competitive, foreign policy relationships with each other. Will Washington, London, Brussels, Paris, and Berlin want to act as a joint transatlantic unit in addressing major foreign policy challenges? Alternatively, will they want to maintain some strategic divergence from each other, given differing ideological outlooks? Either way, the immediate issue for the EU and the United Kingdom this fall will be whether their existing close foreign policy cooperation (such as on Iran) is impacted by—or inoculated from—any wider tensions between them as the Brexit endgame approaches.