President Trump, the U.S. Security Guarantee, and the Future of European Integration

January 17, 2017
Hans Kundnani
18 min read
Photo Credit: StockPhotosLV / Shutterstock

Photo Credit: StockPhotosLV / Shutterstock


The election of Donald Trump as U.S. president could have consequences for the internal dynamics within the EU and thus for the European project itself. Historically, the U.S. security guarantee was the precondition for European integration. The question now is whether, given that the EU has not evolved into a full political union or become independent of the United States in security terms, the new doubt about the security guarantee could lead to a process of disintegration. Military power could even once again become a factor in relations between EU member states and, in the worst case scenario, security competition between EU member states could re-emerge and security dilemmas could be reactivated — as realist international relations theorists argued would happen if the United States withdrew from Europe after the end of the Cold War. In order to respond to this new situation, Europeans will now need to demonstrate much greater creativity and flexibility than they have since the euro crisis began seven years ago.

Discussion about the implications of the election of Donald Trump as U.S. president for Europe has so far focused on the president-elect’s lack of a clear commitment to NATO and the need for Europeans to therefore take greater responsibility for their own security. As European Commission President Jean-Claude Juncker put it, “If Europe does not take care of its own security, nobody else will do it for us.”[1] There has also been discussion of the implications of a more inward-focused United States under President Trump for EU policy towards its eastern and southern neighborhood. The fear is that he might seek to strike a “grand bargain” with Russia — in particular in order to cooperate with it against the self-proclaimed Islamic State — that would in effect recognize a Russian sphere of influence in Eastern Europe.

It is still unclear whether President Trump will follow through on some of the more radical statements he made during the campaign and in particular define the American interest in a narrower way and take an approach to NATO that breaks with decades of U.S. foreign policy. In this context, fears about European security and neighborhood policy are fully justified — and are the most urgent challenge for Europeans. But if the uncertainty about the U.S. security guarantee continues, there is also another question about what they should think that has remained largely unexamined. That is the question of whether the election of Trump could also have consequences for the internal dynamics within the EU and thus for the European project itself.

A Precondition for European Integration

Europeans like to think of the transformation of international politics on the continent that followed World War II and culminated in the creation of the European Union as a magnificent achievement of their own making. According to this narrative, Europeans finally learned the lessons of their own disastrous history of conflict and resolved to make war between them “not merely unthinkable, but materially impossible,” in the words of the Schumann Plan of 1950 that led to the European Coal and Steel Community — the first, historic step in the process of European integration.[2] This narrative, centered on a visionary reconciliation between France and Germany, seemed to be confirmed when the EU was awarded the Nobel Peace Prize in 2012.

Could doubt about the U.S. security guarantee lead to disentegration?

However, the reality is more complex. Historically, the U.S. security guarantee was the precondition for European integration and in particular for the EU as a “peace project.” In an important article published in 1984, Josef Joffe showed how American power “pacified” Europe — that is, “muted, if not removed, ancient conflicts and shaped the conditions for cooperation.”[3] By extending the security guarantee, the United States removed what realist international relations theorists see as the prime structural cause of conflict among states: the search for security. In particular, the U.S. security guarantee reassured France against the possibility of a resurgent Germany. Thus, as Joffe put it, “by protecting Western Europe against others, the United States also protected the half-continent against itself.”[4] Economic interdependence would not have been possible without the confidence this created.

One “pro-European” who recognized the crucial role of the United States was former German Foreign Minister Joschka Fischer. Looking back on the process of European integration in his much-cited Humboldt speech in 2000, he argued that “the core of the concept of Europe after 1945 was and still is a rejection of the European balance-of-power principle and the hegemonic ambitions of individual states that had emerged following the Peace of Westphalia in 1648.”[5] But he went on to say that “two historic decisions in the middle of the last century” made this transformation of international relations in Europe possible: first “the USA’s decision to stay in Europe” and second “France’s and Germany’s commitment to the principle of integration, beginning with economic links.”[6]

Many Europeans hoped they could eventually outgrow their strategic dependence on the United States. Some even saw the EU as a potential counterweight to American power. This was part of the thinking behind the creation of the European single currency and the development of a European Security and Defence Policy. But, as the sixtieth anniversary of the Treaty of Rome approaches, the EU remains a long way away from “strategic autonomy.” During the post-Cold War period, conflicts from Kosovo in 1999 to Libya in 2011 have again and again demonstrated just how dependent Europeans were on Americans to carry out even limited military interventions in their own neighborhood — let alone to defend themselves against a theoretical attack from a hostile power such as Russia.

Meanwhile European integration has also stopped well short of a political union. In other words, international relations still exist within the EU. Clearly, international politics within the EU is not the unmitigated anarchy of realist theory. But although EU member states may be semi-sovereign and constrained by institutions, they remain unequal and have preferences and use power to impose these preferences on others. The question now is whether the new doubt about the U.S. security guarantee could lead to a process of disintegration. In other words, how resilient is the European project? In theoretical terms, this is an argument between liberals and realists: whereas liberals believe economic interdependence and institutions shape relations between states, realists see them as a function of power relations between states.

Most Europeans will reject the idea that the election of Trump might lead to disintegration. Even those who accept that the U.S. security guarantee was historically the pre-condition for European integration will find it hard to imagine that the doubt about it could now put the process of integration into reverse. After all, Europeans have surely moved on since the 1950s when the European project began? Some will even think the election of Trump, which they overwhelmingly opposed, could be the catalyst for further integration — and perhaps even the “completion” of the European project.[7] Since the election of Trump, there have been many calls for Europeans to pull together — and, as usual, some hopes that a crisis might be an opportunity. In particular, the hope is that the EU can now create a real “defense union” and become independent of the United States in terms of security.

It is possible that this will happen, though it is extremely difficult to see how Europeans could become independent of the United States in security terms without spending vast amounts of money, which they seem unwilling to do even now. In particular, Germany remains committed to a gradual increase in defense spending.[8] But even if the practical challenges of European security and defense policy could be overcome, the optimistic view assumes a large degree of unity between EU member states in how they respond to the new situation created by the election of Trump. However, there are reasons to think that, rather than creating unity among Europeans, the election of Trump and the radical uncertainty about the international order it has created may divide Europe.

Centrifugal Forces

If the European project were in better shape, there might be grounds for optimism about the future of European integration even though it remains incomplete. But the events of the last six years have badly damaged the EU. The euro crisis created a new fault line between creditors and debtors within the eurozone and dramatically increased tensions between member states. The refugee crisis made things worse. In particular, the use of qualified majority voting to force through a plan to resettle refugees has created huge resentment and opposition to further integration in central European member states — and exacerbated fears among other member states that they too could be forced to accept decisions in other policy areas. Even traditionally pro-European countries like Italy have become much more Eurosceptic.[9]

It is now extremely hard to see how it would be possible to move forward with further integration in the EU. In particular, it is politically impossible to take major steps in integration that would require treaty change. Perhaps the most important shift is the change in attitudes towards European integration in Germany, which has now become a status quo power in Europe and opposes further integration (except some tightening of fiscal rules). The most striking illustration of this shift is the change in the attitude of German Finance Minister Wolfgang Schäuble — seen as the most “pro-European” member of Chancellor Angela Merkel’s government. Before the British referendum in June, he said in an interview that the EU couldn’t simply react to a British vote to leave the EU with a call for more integration.[10]

There is lack of clarity about the causality behind European disentegration.

While it is hard to see how the EU can move forward with integration, it is also widely recognized that the status quo in the EU and – in particular in the eurozone – is unsustainable. This leaves the possibility of disintegration. European integration had long been considered a one-way process: even if it sometimes stalled, as it did during the late 1960s and 1970s, there was no going back. But this assumption has been challenged in recent years. There has been much discussion of European disintegration as a phenomenon and even attempts to belatedly develop theories of disintegration to better understand how the process might work.[11] In particular, based on neo-functionalist theories of integration, there has been discussion of possible “spillback” effects — in other words, how disintegration in one policy area could lead to disintegration in other policy areas just as integration in one policy area led to integration in other policy areas (“spillovers”).

Meanwhile, there has in recent years been much talk of “centrifugal forces” among policymakers, though the concept has only been vaguely defined. In particular, it is not clear whether the “forces” were Eurosceptic parties or some structural factors behind their rise — and therefore what, if anything, can be done to stop or respond to them. In other words, there is a lack of clarity about the causality behind European disintegration: is it being driven by the Eurosceptic parties themselves or is the rise of the Eurosceptic parties itself a symptom of a deeper cause? In any case, with the vote by the British people to leave the EU, the first major step in European disintegration has been taken, though it remains to be seen what “Brexit” means.

However one understands these “centrifugal forces,” it seems likely that the election of Trump will strengthen them. Trump has aligned himself with Eurosceptic figures such as Nigel Farage, who he suggested should become the British ambassador to the United States. Meanwhile, the dependence of EU member states on the United States for their security will mean they will try to work with President Trump in different ways to achieve concessions in areas of importance to them. Thus the Baltic States and Poland will likely focus on persuading the Trump administration to maintain the U.S. commitment to NATO. Others, particularly in the south of Europe, will sympathize with the idea of reaching an accommodation with Russia — especially if it helps end the conflict in Syria and above all stop the flow of refugees towards Europe.

Worst Case Scenarios

Beyond disintegration, there are also other possible ways in which the doubt about the U.S. security guarantee could transform relations between EU member states. In particular, it is possible that military power could even once again become a factor in relations between them — in other words that they could use it as leverage. Although military capabilities have allowed countries like France and U.K. to project power beyond Europe, they did not give them power within the EU until now. As EU member states could not even threaten to use military force, let alone actually use it, so it could not be used as leverage with other member states. Because of the U.S. security guarantee, other EU member states did not depend on those capabilities. But that may now change.

Again, Brexit is relevant here: it is certainly possible to imagine the U.K. using its military capabilities as leverage in its negotiation with the EU, especially if they become more acrimonious. In fact, the U.K. may already be doing this. When Prime Minister Theresa May held talks with her Polish counterpart in Downing Street on closer security cooperation between the two countries, the Defense Secretary Michael Fallon was asked whether the U.K. was using its military clout to try to secure a better Brexit deal with Poland. (Fallon rejected the suggestion and said such a move would be “a little cynical.”[12]) But in the context of uncertainty about the U.S. security guarantee, it is also possible to imagine France using its military capabilities as leverage against Germany — for example in its negotiations with Germany on EU fiscal rules.

Trump may withdraw from Europe, turning a bipolar system in a multipolar one.

An even darker possibility is that security competition between EU member states could re-emerge and security dilemmas could be reactivated — as some realist international relations theorists argued would happen after the end of the Cold War. In an article published in 1990, John Mearsheimer predicted that the end of the Cold War could lead to the end of the “long peace” in Europe.[13] His argument was that what had maintained peace in Europe since 1945 was not economic interdependence or the spread of democracy, as liberals believed, but the bipolar Cold War order. In particular, there were two reasons for the transformation of relations between EU member states. First, “old-fashioned balance of power logic mandated cooperation among the Western democracies.”[14] Second, the U.S. presence “mitigated the effects of anarchy” and “facilitated cooperation among them.”[15]

The article explored possible scenarios that might become reality if the Soviet Union and the United States completely withdrew their military forces from Europe. Mearsheimer argued that this would create a multipolar rather than bipolar Europe, which would be inherently more unstable and could lead to war. But he assumed that the United States would only withdraw its forces if the Soviet Union also did so. After all, it was the Soviet threat that kept them there. What happened instead, of course, was that the Soviet Union collapsed and NATO enlarged to include central and Eastern European countries including some that were formerly part of the Soviet Union. But although the Soviet threat thus disappeared, U.S. forces remained in Europe — albeit in smaller numbers than during the Cold War. Thus Mearsheimer’s thesis was never tested.[16]

Now, however, a scenario may be emerging that is different from the one Mearsheimer imagined but may nevertheless test his thesis after all. Despite a new threat from a revisionist Russia and even the perception of a “new Cold War,” the United States under Trump may do what Mearsheimer feared all along — that is, withdraw from Europe and thus turn a bipolar system into a multipolar one. It is difficult to know what even realist theory would predict in this scenario. On the one hand, fears among member states of relative-gains had been mitigated in part by the U.S. security guarantee could return.[17] On the other hand, European democracies could still be forced together because of the renewed threat from a resurgent Russia. (Even if EU member states do pull together in this way, however, it may not be particularly reassuring because of the inefficient way that balance of power dynamics work in a multipolar system.)

One important question in this scenario is around nuclear proliferation. Mearsheimer argued that, in the absence of the U.S. nuclear umbrella, the stability of Europe would depend to a large extent on the proliferation of nuclear weapons. He argued that the most stable scenario (though still more unstable than the bipolar Cold War system) would be one of limited and managed proliferation in which only Germany acquired nuclear weapons. Other scenarios, such as a nuclear-free Europe or mismanaged proliferation, would be even more unstable. Mearsheimer appears to have underestimated the deep opposition to nuclear weapons in Germany. But it is striking that, since the election of Trump, a number of voices in Germany have already suggested the need for a rethink and called either for a European nuclear deterrent or even an independent German nuclear deterrent.[18]

Structural Pressures

The new doubt about the U.S. security guarantee will not lead inexorably to European disintegration. But the election of Trump and the uncertainty about the security guarantee it has created has implications not just for the European neighborhood but also for the internal dynamics within the EU. Moreover, whether Europeans can prevent disintegration is not just a question of political will. Rather, there are structural pressures related to the relationship between the U.S. security guarantee and the European project that increase the likelihood of disintegration. Unless European policymakers engage with these structural pressures and take steps to counter them, they are less likely to be able to respond to the situation created by the election of Trump and the uncertainty about the U.S. security guarantee it has created.

In order to respond to the new situation created by the election of Trump and to protect the EU, Europeans need to rethink the approach they have taken over the last seven years since the euro crisis began. Since then, progress in reaching agreement at an EU level on various issues has often been limited because member states — especially Germany — have refused to make concessions on principles and to link issues as part of a kind of intra-EU grand bargain. But given the overwhelming interest EU member states have in preventing European disintegration and the possible emergence of the worst case scenarios described in this paper, Europeans will need to demonstrate much greater creativity and flexibility than they have so far. This has two particular consequences.

Europeans need to rethink the approach they have taken over the last seven years.

First, an intra-EU grand bargain is now more necessary than ever because European security now depends on it. In particular, Germany will need to make concessions to France on economic issues, for example around EU fiscal rules, because it needs French military power. Second, the EU can no longer afford an acrimonious negotiation with the U.K. and therefore needs to rethink its Brexit strategy.[19] The exact details of the economic relationship between the EU and the U.K. are no longer as important as they seemed before the election of Trump. As important for the EU is to maintain a good relationship with the U.K. and to reach what Fischer calls a “post-Brexit cooperative strategic arrangement with the U.K.”[20] In short, Europeans need to see the big picture — and how it has been redrawn by the election of Trump as U.S. president.


I would like to thank Olivia Knodt for her help with research and Rachel Tausendfreund for helping me develop the argument in this brief on European integration and the Transatlantic relationship, as well as for editing the text. Anand Menon and Jana Pulglierin provided helpful comments on an earlier draft. I would also like to thank my colleagues at the Transatlantic Academy in Washington, DC, for the stimulating discussions we have had over the last few months that have informed the argument in this brief.


[1] James Kanter, “E.U. Plans Big Increase in Military Spending”, New York Times, 30 November 2016,

[2] Schuman Declaration, 9 May 1950, available at information/symbols/europe-day/schuman-declaration/index_en.htm.

[3] Josef Joffe, “Europe’s American Pacifier,” Foreign Policy, No. 54 (Spring, 1984), pp. 64-82, here p. 68.

[4] Joffe, “Europe’s American Pacifier,” pp. 68-9.

[5] Joschka Fischer, “From confederacy to federation. Thoughts on the finality of European integration”, Speech at the Humboldt University, Berlin, 12 May 2000.

[6] On these two decisions, see also Robert Kagan, Of Paradise and Power. America and Europe in the New World Order (New York: Vintage, 2004), pp. 72-3. Kagan spells out that “the latter could never have occurred without the former.”

[7] On European attitudes to Trump, see Pew Research Center, “Europeans express confidence in Obama and Clinton, but not Trump”, 27 June 2016,

[8] “Merkel: Germany must boost defense spending, unlikely to meet NATO goal soon”, Reuters, 23 November 2016,

[9] See Mark Leonard and José Ignacio Torreblanca, The Eurosceptic surge and how to respond to it, European Council on Foreign Relations, April 2014,

[10] “Britain Is a Leading Nation”, Spiegel interview with Wolfgang Schäuble, 10 June 2016, Schäuble said: “In response to Brexit, we couldn't simply call for more integration. That would be crude, many would rightfully wonder whether we politicians still hadn't understood. Even in the event that only a small majority of the British voters reject a withdrawal, we would have to see it as a wakeup call and a warning not to continue with business as usual. Either way, we have to take a serious look at reducing bureaucracy in Europe. And in some areas, we also need to find our way back to the member states assuming more autonomy, as the British are demanding.”

[11] See for example Annegret Eppler and Henrik Scheller (eds.), Zur Konzeptionalisierung europäischer Desintegration: Zug- und Gegenkräfte im europäischen Integrationsprozess (Baden-Baden: Nomos, 2013); Hans Vollaard, “Explaining european disintegration”, Journal of Common Market Studies, 52 (5), 2014, pp. 1142-59; Douglas Webber, “How likely is it that the European Union will disintegrate? A critical analysis of competing theoretical perspectives”, European Journal of International Relations, 2013; Jan Zielonka, “European Disintegration? Elusive Solidarity”, Journal of Democracy, October 2012; Jan Zielonka, Is the EU doomed? (Cambridge: Polity Press, 2014).

[12] See Rob Merrick, “Brexit deal must protect the rights of one million Poles in Britain, PM warned”, Independent, 28 November 2016,

[13] See John J. Mearsheimer, “Back to the future: instability in Europe after the Cold War”, International Security, 15: 1, Summer 1990, pp. 5–56.

[14] Mearsheimer, “Back to the Future”, p. 46.

[15] Mearsheimer, “Back to the Future”, p. 47.

[16] See John J. Mearsheimer J, “The future of the American pacifier”, Foreign Affairs 80(5), 2001, pp. 46–61; “Why is Europe peaceful today?” European Political Science 9(3), 2010, pp. 387–397.

[17] On this point, see Mearsheimer, “Back to the Future”, p. 47.

[18] Roderich Kiesewetter, a Christian Democrat member of the Bundestag, proposed a European nuclear deterrent. See Andrea Shalal, “German lawmaker says Europe must consider own nuclear deterrence plan”, Reuters, 16 November 2016, Berthold Kohler, one of the publishers of the Frankfurter Allgemeine Zeitung, called for an independent German nuclear deterrent. See Berthold Kohler, “Das ganz und gar Undenkbare”, Frankfurter Allgemeine Zeitung, 27 November 2016, For a discussion of the German debate, see Ulrich Kühn, “The sudden German NU.K.e Flirtation”, Carnegie Endowment for International Peace, 6 December 2016,

[19] See Mark Leonard, “The Coming Brexit Tragedy”, Project Syndicate, 21 December 2017,

[20] Joschka Fischer, “Europe’s New “Indispensable Nations”, Project Syndicate, 5 January 2017,