Xenia Wickett is Head of the US and the Americas programme at Chatham House. This piece has been published in collaboration with Chatham House. The views expressed are the author's own. This piece was also published at the Chatham House website.
The U.S.-U.K. Special Relationship is in decline, and a British decision to leave the European Union would hasten its demise. As Great Britain increasingly becomes just one of America's many strategic relationships, Brexit would speed the transfer of U.S. attention and energy from the United Kingdom to the continent. This, however, does not need to be inevitable. The necessary ingredient to reverse this decline is stronger British leadership internationally.
The U.S. government has made it abundantly clear that its preference is to see Britain remain in the European Union. In January 2013, when British Prime Minister David Cameron had not yet committed to a referendum on Britain's EU membership, Phil Gordon, the U.S. assistant secretary of state for European affairs, bluntly stated that it is in the American interest for the United States "to see a strong British voice in that European Union." The fact that a senior U.S. official would go so far - to be seen to intervene so early in a divisive domestic political issue - spoke volumes about how important this is to America. This week, U.S. President Barack Obama will visit the United Kingdom to send an equally firm, if polite, message to the British public.
Why does the U.S. want the U.K. to remain in Europe?
From the U.S. perspective, there are three principal elements that the United Kingdom brings to the table in the bilateral relationship. The first stems from Britain's capabilities, particularly in the military and intelligence arenas. US-U.K. intelligence sharing - each country is the other's closest partner - has a long history dating back to the Second World War. For good or ill, the United Kingdom has been among America's leading allies in every major conflict the United States has been involved in for the last quarter of a century - in the Gulf War, Bosnia and Kosovo, Afghanistan, the war in Iraq, and the interventions in Libya, as well as current operations against ISIS in Iraq and, belatedly, Syria.
The second relates to the political value of having a reliable partner in international engagements - and thereby avoiding the perception of acting unilaterally. Shared history and values, and thus often perspectives (as well as capabilities) have ensured that the United Kingdom has long been the first port of call for the United States when Washington seeks to solve international problems or build coalitions. At the same time, Britain's historical global reach and diplomatic experience around the world (not least in areas of current concern such as Afghanistan, Pakistan, Israel and Palestine, and Iraq) have provided American policy-makers with valuable input on foreign policy issues that has contributed to their own internal decision making.
The third area of added value for the United States is Britain's place in the European Union. While British and U.S. policy preferences may at times diverge, as they have recently on the Israel-Palestine issue, for example, their common outlooks and interests mean that Britain is the closest thing that the United States has to having a voice in the European Union. At the same time, the United States also sees Britain as the country most likely to support an open trade and investment agenda and a more proactive approach to dealing with the challenges in Europe's neighbourhood, policies that leaders in both countries agree are necessary to make the European Union a more effective actor and a better partner to the United States on the international scene.
The transition from U.S.-U.K. ties to U.S.-European ties
In recent years, however, the United States has begun to diversify its relationships within Europe, in part as Britain has become unable or unwilling to step up and fulfill these three elements of paramount importance to the US.
Defense and intelligence
With regards to defense capabilities, it is no longer the United Kingdom that the United States inevitably looks to first. In Libya, the operation that started with the defense of Benghazi from Moammar Gadhafi's forces in March 2012 (which eventually came to remove Gadhafi himself) was jointly led by the French and the British, although then-French President Nicolas Sarkozy appeared to be the driving force. More recently, it was the French with whom the United States partnered in responding to the terrorist activities in Mali, and Paris was first to support the United States in action in Syria. (This followed a British parliamentary vote to stay out in August 2013, and a belated vote to act in December 2015.) But in recent years others have worked more closely with the United States militarily as well, including in particular Poland and Denmark - although with the new government in Poland, the relationship might wither again.
This trend toward more diversified military engagement with other European states looks set to continue in the near term. Despite taking a tough position in the 2014 NATO Summit to reinforce the commitment of NATO countries to spend 2 percent of GDP on defense, the Cameron government came very close to falling below this line in 2015, after five years of real defense cuts. The eventual decision to commit to meet this target, along with the newly released Strategic Defence and Security Review (SDSR), have somewhat reassured American policymakers of the United Kingdom's continued ambition and capabilities. But there remains a lack of U.S. confidence, a feeling that this is only a temporary uptick in British attention to defense. Meanwhile, America will continue to expand its horizons.
The story on intelligence sharing is slightly different, but here too obstacles have arisen in the close U.S.-U.K. exchange of information. Since the end of the Second World War, the United States and United Kingdom have been part of the Five Eyes alliance - with Australia, New Zealand, and Canada - that allows its members to closely share intelligence. And arguably, within the Five Eyes, the links between Washington and London are the closest of all. However, more recently, tensions have emerged. Over the past five or so years, the British judicial system in particular has pushed back on U.S. confidentiality rules in ways that make the U.S. intelligence services nervous of continuing to share information; given the current close relationship, this could be more of an obstacle than it is for other countries sharing intel with the United States.