In the wake of the British referendum, U.S. Vice President Joe Biden noted, "We would have preferred a different outcome." A few days later, Secretary of State Kerry said that it was still possible to "walk back" on Brexit. Neither the disappointment nor the hope that the situation could still be reversed came as a surprise from the American side. Indeed, over the last six decades, Washington spared no effort to put, then keep, in the EU their favorite ally. The reason is simple. As explained by the U.S. Embassy in London, the European Union is "the world’s most important organization to which the United States does not belong". In order to make its voice heard, the U.S. needs their "man inside" or, in diplomatic terms, "the expression within the EU of common U.S.-UK attitudes through UK membership". Except that British voters opted for the exit...
From the outset, the United States had worked tirelessly to ensure that London will enter a Europe that was about to take shape. When the British refused to participate in the negotiations on the ECSC (European Coal and Steel Community) voices even rose in Congress to threaten them with "cutting off Marshall Aid to Britain if it persisted in opposing membership". However, this threat did not materialize and the British government took ten more years to finally accept what Prime Minister Harold Macmillan called "the grim choice".
When he ended up applying for membership in the EEC (European Economic Community or the Common Market) in 1961, his decision was not unrelated to the firm injunctions he received from the other side of the Atlantic Ocean. Injunctions that were relayed insistently by U.S. diplomat George Ball, co-author of the Schuman Plan (Europe’s founding document), and future Deputy Secretary of State. As the British Ambassador to Washington observed at the time: the United States had "a heavy stake in the success of the negotiations" on the UK’s entry.
For David Ormsby-Gore, there was no doubt: "the least reaction we must expect in the United States, should we elect to remain outside the Common Market, is perplexity and disappointment, and an unhelpful neutrality towards the consequences of our decision." Adding that Washington "would be unlikely to accept failure as final and before long their salvage engineers would be at the scene of the wreck."
This is exactly what happened after the first veto by General de Gaulle to the UK’s entrance, a veto meant, in his own words, to prevent the EEC from dissolving into "colossal Atlantic Community under U.S. direction and leadership [that would] quickly absorb the European Communities." Three years had hardly passed and President Johnson was already back on the task. He explained to the new Prime Minister Harold Wilson, initially anti-integrationist, that "Your entry would certainly help to strengthen the West" and that the United States would contribute "anything we might do to smooth your path."
Fast-forward fifty years, and the U.S. administration, under President Obama, resuscitated the same massage, only this time to avoid the British exit from the European Union. As early as in 2015, the American President reiterated that "Having the United Kingdom in the European Union gives us much greater confidence about the strength of the transatlantic union". Apparently so much so that he went as far as to meddle in the final stretch of the referendum campaign. Namely by warning that Britain would go to the "back of the queue" for trade deals with the U.S. if it votes to leave Europe.
In case this was not sufficiently clear, President Obama went on to explain that "the outcome of your decision is a matter of deep interest to the United States". He also evoked "The tens of thousands of Americans who rest in Europe’s cemeteries as a silent testimony" to transatlantic interdependency. Calling to British voters, the American president stressed that "The United States sees how your powerful voice in Europe (…) keeps the EU open, outward looking, and closely linked to its allies on the other side of the Atlantic." The U.S., therefore, needs British "influence to continue – including within Europe".
Even before its launch, the U.S. approach to European integration was a fundamentally ambivalent one. As a State Department report from 1943 clearly stated: "like the little girl in the nursery rhyme, a European Union, from the point of view of our long-run economic interests, can either be very, very good, or horrid". The more Europe gains in economic power and tries to assert itself politically, the more this initial ambivalence turns into a growing mistrust of the project. Zbigniew Brezinski, emblematic figure of U.S. diplomacy, concluded in the early 2000s: "[A] politically powerful Europe, able to compete economically while militarily no longer dependent on the United States would inevitably contest American preeminence" and could confine its scope "largely to the Pacific ocean".
To counter such a development, Washington had identified two major fronts from the outset. In the economic field, Europe had to remain largely open and without even a hint of protectionism, especially not in the strategic sectors and/or those of particular interest to U.S. trade. In the defense-military area, the Atlantic Alliance was meant to structure and perpetuate Europeans' dependence on the United States. The two aspects have always been intimately linked, by the way. As President Nixon very plainly put it: "Europeans cannot have the United States’ participation and cooperation on the security front and then proceed to have confrontation and even hostility on economic and political front."
Britain’s role has always been to ensure that, in both aspects, the EEC, and later the European Union, develops in a way that is consistent with America's interests and vision. Hence their indefatigable and widely successful efforts to make Europe both economically ultra-liberal and devoid of any meaningful military dimension. Whether successive British governments do so because they actually believe in it or because their excessive dependence leads them to express, or even internalize U.S. priorities, the result is the same: UK activism in Europe serves first and foremost American interests (and oftentimes against Britain’s own interests).
On the two crucial "fronts" from America's point of view, London has done everything to steer the whole of the EU in the "appropriate" direction. On the economic front, it has always pushed for a supermarket-type Europe, without genuine policies that would counterbalance the often one-sided openness and the distorting effects of pure market forces. Furthermore, the UK never ceased working on the vast project of a large transatlantic common market. It has done so with such a zeal that even the iconic figure of previous attempts, former European Commissioner Sir Leon Brittan spoke ironically of the United Kingdom as being the "most enthusiastic cheerleader" of the TTIP, the latest avatar of the draft free trade treaty.
According to the U.S. Congressional Research Service, "senior Administration officials have expressed concern that a UK break from the EU would reduce U.S. influence in Europe, weaken the EU's position on free trade, and make the EU a less reliable partner on security and defense issues." On this latter point, it is to be noted that according to the widespread U.S./UK view, a "reliable partner" is an EU that respects the primacy of the Atlantic Alliance and is confined to sympathetic civilian missions or (very) small-scale operations, and only if pre-approved by NATO/America. So far, the United Kingdom has always been there to ensure that this will be indeed the case for each and every new European "defense" initiative.
In 1964, Sir Con O’Neill, then British Ambassador to the Communities wrote that "if European unity proceeds on the basis of the Six only", the EEC and the United States "may fall out with each other". Former President George W. Bush's Secretary of State Condoleezza Rice recently remarked at a conference at Chatham House that "It is a very different Europe if it is a continental Europe." Indeed, then and now, U.S. concerns invariably refer to the consequences to be expected in the military and economic spheres.
On the commercial front, Brexit means that the transatlantic free trade negotiations will automatically lose their most fervent supporter. More generally, as Charles Grant, director of the Centre for European Reform, pointed out at a parliamentary hearing years ago: in the absence of the United Kingdom, "we are forcing the Germans to work much more closely with the French, faute de mieux, and there is a risk that the Germans will become less free trade oriented". From there, there would be only one step towards the establishment of a kind of "Buy European" policy that the United States, while pursuing a protectionist policy for its own products and industries, has always categorically opposed.
The other set of Anglo-American fears concerns the post-Brexit evolution of European defense. As a recent British Parliament report said, Britain’s current policy "prevents the creation of this active EU defence identity, opposing, for example, the establishment of joint EU military operational headquarters. It is therefore possible that “Brexit” and the absence of this continuing British veto could free the EU to pursue a more cohesive and effective common defence policy". Such an evolution could threaten "to decouple it [the EU] from NATO, damaging the integrity of the transatlantic alliance" and the EU developing a "different view"from the UK and USA on issues such as relations with Russia... 
Alas, we are far away from the EU "emancipating" itself and taking an independent, interest-based stance in both the economic and defense areas. Over the last decades, and in particular following the U.S./UK-inspired big enlargement, the European Union as a whole has been derailed off its original course and largely shaped in the image of Britain: over-dependent and over-deferent towards the U.S., as well as fiercely ultra-liberal. The new, post-Brexit context will force the founding countries of the EU to clarify. With London out of the picture, it will quickly turn out whether it has really been the sole United Kingdom at the origin of the EU’s multiple derailments and blockages. Or if others have simply taken advantage of the UK’s presence and policies to conceal their own choices.
 “U.S. would have preferred a different Brexit outcome – Biden”, Reuters, 24 June 2016.
 “John Kerry: Brexit could be 'walked back'”, The Guardian, 29 June 2016.
 Government foreign policy towards the United States, Eighth Report of Session 2013–14, 25 March 2014.
 Chris Patten, Cousins and Strangers – America, Britain, and Europe in a New Century, Times Books, 2006, p. 110.
 John Dulbrell, A Special Relationship, Anglo-American Relations in the Cold War and After, Palgrave Macmillan, 2001, pp 178-179.
 President de Gaulle’s Press conference, 14 January 1963.
 Dulbrell Op. Cit. p181.
 “Britain needs to stay in EU to support transatlantic ties”, Obama says, Reuters, 24 July 2015.
 “Barack Obama says Brexit would leave UK at the 'back of the queue' on trade”, BBC News, 22 April 2016.
 Barack Obama: As your friend, let me say that the EU makes Britain even greater, The Telegraph, 23 April2016.
 Patten Op.Cit. p110.
 Zbigniew Brzezinski, The Choice: Global Domination or Global Leadership, 2004, Perseus Books, p.91.
 Richard Nixon, 15 mars 1974. In Public Papers of the Presidents of the United States: Richard M. Nixon, 1974, p276.
 See Hajnalka Vincze, The Transatlantic Dimension of British Euroscepticism, in The UK Challenge to Europeanization - The Persistence of British Euroscepticism, ed. K. Tournier-Sol - C. Gifford, Palgrave Macmillan, 2015.
 Oral Evidence by Lord Brittan before the UK Parliament’s Select Committee on the European Union, 10 October 2013.
 Derek E. Mix, The United Kingdom: Background and Relations with the United States, CRS report, 29 avril 2015; The United Kingdom and the European Union: Stay or Go?, CRS Insight, 20 juin 2016; United Kingdom Votes to Leave the European Union, CRS Insight, 24 juin 2016.
 See Hajnalka Vincze, L’Europe de la défense, éternelle pomme de la discorde entre la France et le Royaume-Uni, 31 January 2014. For an detailed analysis on the evolution of European defense, see from the author: Slippery slope : the Need to Reverse the re-Atlanticisation of European Defence, The Federalist n°2-3, 2013.
 Dumbrell Op.Cit. p180.
 Condoleezza Rice, Renewing the Transatlantic Alliance, Chatham House, 29 octobre 2015.
 Oral Evidence by Charles Grant, director of the Centre for European Reform, before the UK Foreign Affairs Committee, 10 July 2012.
 Hajnalka Vincze, Europe européenne ou Europe atlantique : une question de «préférence»…, La Lettre Sentinel n°47, October 2007 ; and Nicole Bricq : « Les États-Unis sont très protectionnistes » interview with the Minister for External Trade, Le Figaro, 5 October 2013.
 House of Commons Foreign Affairs Committee, Implications of the referendum on EU membership for the UK’s role in the world, Fifth Report of Session 2015–16, 26 April 2016, p28.