In the past few years Europe faced several severe challenges both internally and externally. The way how the EU will deal with issues such as a changed security environment is crucial for its further development.
Since a couple of years now, the EU is exposed to an ever more volatile security environment as show the last few years. After the 2013-2014 Euromaidan uprising, war started in Eastern Ukraine and Russia annexed Crimea in 2014. In 2015, the refugee crisis escalated, with the Syrian and Libyan wars pushing and pulling refugees towards the EU’s southern shores and, for many, to the deadly debts of the Mediterranean. In 2016, a failed coup attempt in the city of Ankara in Turkey pushed Erdogan in what many would call an authoritarian overdrive with serious ramifications for the EU-Turkey relationship and Turkey’s ever more complex relationship with NATO. A month earlier, a majority of British voters voted in favour of Brexit, exposing both the UK and the EU to a range of new questions and challenges. In 2017, Donald Trump entered office as U.S. President, and his ideas about the position of America in the international security and trading system, combined with the impulsiveness of some of his actions or statements, not to the least with respect to NATO, not only ruffled feathers, but compounded the already existing sense of instability in Europe.
This instability in the EU’s security environment was also tangible inside the EU itself. There is the pressure that the refugee crisis puts on the EU member states, ranging from the material and financial pressures on the first receiving ones such as Greece and Italy, to its political translations into the elections in several countries (the Netherlands, France, the UK, Germany, Italy). Furthermore, tensions mark the bilateral relations between several EU member states and the Erdogan government, particularly in the run-up to the April 2017 constitutional referendum in Turkey and to the German elections in September 2017. Finally, the ISIS terrorist attacks across the EU, or the attacks to which ISIS claims involvement, span an ever growing list of locations around Europe (Paris, Copenhagen, Brussels, Nice, Munich, London, Berlin, Stockholm, Barcelona and Turku).
The combination of these developments tremendously increase the sense of vulnerability inside the EU and, to a certain extent, the feeling that the EU has to try – more than in the past – to take its destiny and security more into its own hands. For some member states, this feeling is more than just theoretical or academic. It is urgent and acute. This is not only the case for Italy and Greece where new refugees arrive every day and where pressure on resources immediately transform into pressure on political leaders, but also for countries such as Estonia, Latvia, Lithuania and Poland, and their concerns about Russia and the threat it seems to represent.
Public Senses of Insecurity
There is a growing sense of insecurity in Europe. This is the case with public opinion as much as with political leaders across the continent. According to Pew Research, Europeans identify ISIS terrorism as the leading security threat, surpassing the influx of refugees, the top perceived threat in 2016. However, refugee influx remains a big concern across Europe and a main concern in Hungary. Russia’s power and influence is also considered to be a major threat alongside the U.S. and China. Poland stands out in this regard, and to a lesser extent France, the Netherlands, the UK and Sweden. At the same time, public opinion in Germany, Spain and Greece perceives American power and influence more as a threat than the Russia one. In Italy, China’s power and influence is perceived to be a stronger threat. Pew does not provide any figures on the evolution in the perceived threats of Russia’s global power and influence over time but does so with respect to favourable and unfavourable opinions about Russia. Negative views about this country among EU public opinion rose between 2007 and 2017 with a peak in 2014-2015, just during the period in which Russia proceeded with the annexation of Crimea and the war escalated in Eastern Ukraine.
As already indicated, Russia is not the only country for which its global power and influence is perceived to be a major threat. That is also the case for the U.S. and China. In the former case, European perceptions of the U.S.’s power and influence as a major threat grew significantly between 2016 and 2017, undoubtingly as a consequence of Trump’s arrival in the White House. Only in Greece and Poland opinions were different. In the latter, threat perceptions of the U.S. declined rather than increased. In the former, opinions remained unchanged.
Populist Electoral Pressures in Europe
The issues, with which political leaders in Europe are struggling, mirror those of their public opinions, adding to the concern of a collapsing traditional political order in Europe in consequence of right-wing electoral successes. These fears escalated between the Brexit-referendum on 23rd June 2016 and the French presidential elections in April and May 2017. It was as if the survival of the EU itself was at stake, and maybe it was for real . The outcomes of the Dutch elections on 15th March 2017 calmed these fears only to a certain extent as many realised that more than only France’s future was risked in the French elections . Sighs of relief went through European capitals – and to a certain extent beyond – when Macron won the first round in April and certainly when he ultimately won the presidency in May 2017 . At the same time, some observers warned for the risks of such relief. The fundamental factors behind the rise of populist movements in Europe (and beyond) could not be neglected and as such, populist defeats in Europe could not be seen as a “vindication of the status quo”, as was stated succinctly in The Wall Street Journal:
‘(…) for European Union elites, the temptation will be to view the Macron triumph as vindication of the status quo, given Ms. Le Pen’s vow to leave the EU and ditch the euro. It is at most a reprieve .’
And specifically for German Chancellor Angela Merkel, this was an important lesson and concern to be drawn from the French elections. As Ralph Bollmann observes:
‘Dem neuen französischen Präsidenten wo immer möglich zu Erfolgen zu verhelfen, ist Bestandteil von Merkels europäischem Plan – nicht um jeden Preis, aber soweit es mit deutschen Interessen vereinbar ist. Niemand könne ein Interesse daran haben, dass in fünf Jahren die Rechtsradikale Marine Le Pen das westliche Nachbarland regiert, heiβt es in Merkels Umgebung .‘
Indeed, the fundamentals behind the rise of populism are still there, as are those strong feelings of instability as well as a sense of urgency in the search for solutions, while at the same time neither the available institutions, nor European leaders’ limited political capital in a polarised environment allow Europe to readily find them. Also, problems emerge from everywhere and seem to compound one another.
The Ongoing Refugee Crisis
There is the ongoing refugee crisis which – despite reduced media attention in the northern parts of Europe – continues to cause almost existential problems for political stability across the Northern Mediterranean, particularly in Greece and Italy. As Italian Prime Minister Paolo Gentiloni phrased it in a preparatory meeting for the Hamburg G-20 Summit with Merkel and Macron:
‘I flussi migratori non si arrestano. Se non ci aiutate, il rischio è che alle prossime elezioni in Italia trionfino i populisti. (...) Il messaggio è quello di un Paese che non viola le regole, ma che è sotto pressione e chiede il contributo concreto dei colleghi europei .’
The ongoing refugee crisis is a typical example of how one problem feeds another. The question is, indeed, intricately linked with the wider stability problems in North Africa and the Middle East (Libya and Syria in particular) but is also affected by the EU’s relationship with Turkey. Since March 2016, the EU and Turkey concluded an agreement – officially a statement – on illegal migration. Officially, it aims to substitute illegal migration from Turkey to the EU with “organised, safe and legal channels to Europe” and with the payment of three billion euros by the EU to its “Facility for Refugees in Turkey” to help Turkey hosting Syrian refugees . In exchange, Turkey would do its best to stop migrants who try to illegally enter the EU. Even if it faces strong criticisms from NGOs involved in human rights and refugee issues, this deal was (and is) tremendously important to EU political leaders, not least for Angela Merkel. That is why Turkey was able to play hardball during the negotiations on the EU-Turkey Statement in the first place.
Conflicts about the implementation of the Statement by the EU keep popping-up, however, and these are linked to Turkey’s rising – even escalating – tensions with several EU member states, particularly (but not only) Germany, since the failed coup attempt against Turkish president Recep Tayyip Erdogan on 15th July 2016 .
Deteriorating Relations with Turkey
For the Turkish leadership, the failed coup attempt of July 2016 was nothing less than an attack on Turkish democracy and as such, countries like France and Germany as well as the EU as a whole, should have acted accordingly. Instead of criticising Erdogan’s response to the coup attempt and granting asylum to diplomats and military officers suspected of being involved in the failed attempt, European leaders should have shown solidarity with Turkish democracy, for instance by visiting the country in its immediate aftermath . In addition, instead of talking about red lines that were crossed, the EU should start the accession negotiations with Turkey on chapter 23 (judiciary and fundamental rights) and chapter 24 (justice, freedom and security). It is not a surprise, however, that exactly the topics of these chapters are at the core of the EU’s claims about crossed red lines by Turkey since July 2016. The claims are indeed rather fundamental. They point at the massive detainments of tens of thousands of suspected people, the even more massive firing of hundreds of thousands of people in the military, public administration and education (particularly universities) and to the repression to which journalists are exposed. Everyone more or less suspected to be linked to or being involved in the Gülen Movement (Hizmet) faces retribution as Fetullah Gülen himself – the spiritual leader of Hizmet – is suspected to have ordered the coup attempt. Even though ambiguous evidence has been provided until now, the Gülen Movement is treated (and in Turkey widely labelled) as a terrorist organisation – the Fetullah Terrorist Organisation (FETO) – and members and sympathisers are treated as such.
The aftermath of the failed coup attempt did not transform a good relationship into a bad one. EU-Turkish relations were bad and deteriorating already before. Turkey was running out of patience with the ever ongoing but never ending accession process to the EU, and vice versa, the EU was running out of patience with Erdogan and his (ultimately successful) attempts to centralise powers to his favour. But after the failed coup attempt things went from bad to worse. Specifically in the run-up to the Turkish referendum on 16th April 2017, tensions were running high. Members of the Turkish government were impeded to hold rallies in several EU countries – most prominently in the Netherlands and Germany – and Erdogan engaged in an ever more nationalist and insulting language, such as claims about “Nazi practices” in Germany and about the Dutch government consisting of “Nazi remnants and fascists” after a Turkish government minister was denied access to the Turkish consulate in Rotterdam.
Deteriorating relations with a neighbour are always to be regretted. But in the case of Turkey, we are talking about a neighbour of major significance from a strategic point of view as well as from a political one.
Whatever European leaders may have claimed over time, the EU doesn’t really want Turkey as full member. No other applicant state has been allocated the status of an accession country for such a long time as Turkey , even if this may be partly related to Turkey itself and the challenge of adopting the EU acquis. The accession process has indeed become a way to the EU to buy time in order to find a way to structure the EU-Turkish relationship, preferably without Turkey itself becoming a full member. Somewhat cynically, one could claim that Erdogan’s path to autocracy has made it easier for EU leaders to openly expound what every attentive observer already knew for a long time: Turkey will not become an EU member state any time soon. And in Ankara political leaders know this as well. In fact, the failed coup attempt and the EU’s reactions to Erdogan’s response to it did not have a real impact, since the foreign policy of the successive AKP governments clearly points in that direction: Turkey has its own ambitions. It targets its own regional sphere of influence, its own geostrategic orbit. Central Asia stands out as a particular area in this regard, driven by a mutual intelligibility of languages, joint linguistic roots and commonalities in ethnicity. In the same sense, Erdogan’s Turkey sees for itself an important role as prominent player in the Sunni world, relying on its central important religious role during the era of the Ottoman Empire. This makes the situation even more complex as it draws it in the intricacies of the complex relations among Arab countries.
Turkey also has its own immediate concerns. And some of these align remarkably well with those of the EU. It is indeed a matter of regional stability – or in the case of the EU, stability on its south-eastern flank. For Turkey, the concerns are indeed immediately exposed as it is to the spillover effects of ongoing conflicts and wars in the wider Middle East (terrorism, refugees, separatism). For the EU, terrorism and refugees stand out as concerns.
Whatever the mutual feelings may be, these shared concerns and the sheer size of Turkey as a neighbour condemn the EU and Turkey to find a modus vivendi or, after the devastating aftermath of the failed coup attempt, a new modus vivendi. This is even more the case because of the immediate domestic influence of Turkey inside some EU member states, most prominently Germany, France, the Netherlands, Austria, the UK, Bulgaria and Belgium. It is not a coincidence that the immediate aftermath of the failed coup attempt and the run-up to the 2017 referendum could be felt so strongly inside the EU. Political cleavages inside Turkey – including the current polarised situation – reproduce themselves among citizens of Turkish descent inside the EU and are therefore an immediate concern for local political leaders. And they realise that Ankara has the ability to directly weigh in here .
And there is another player that used to try to weigh in on the Turkish-EU relationship: the U.S. That is not a real surprise. Turkey is not just one of the twenty-nine NATO member states. There is its sheer size and strategic location (cf. the strategic importance of the Incirlik airbase for NATO and/or U.S. Middle East operations) and the fact that it belongs to the big military players in terms of its defence budget and the size of its army in the Alliance . Successive U.S. presidents played an important role in keeping the perspective of a Turkish EU membership on the table even if in some cases, they had to do this extremely diplomatically, given European sensitivities about American mingling in internal EU affairs. What the Trump era will bring in this context remains uncertain. At the same time, however, whether Europe likes it or not, it cannot neglect the importance of Turkey, certainly not in an era in which Europe will have to rely more on itself and less on others to solve its problems, and in which developments in its southern and south-eastern neighbourhood directly affects its stability and the political vulnerabilities of its leaders.
Putin’s Russia and the Notion of Hybrid Warfare
Talking about vulnerabilities, neighbourhoods and NATO, immediately brings one to Russia that other big and even potentially more overarching neighbour of the EU. And if there is something that Erdogan and Russian President Vladimir Putin share, it is their strong sense of strategic self-interest and independence and the ambition in their foreign policies. In the case of Putin, this triggers a lot of concern and even fear inside the EU. Concerns about Zapad 2017 (Запад 2017), the Russian-Belarusian joint military exercises between 14th and 20th September 2017 close to Lithuania and Poland – and on the two sides of the so-called almost 100 km long Suvalki Gap between the Kaliningrad oblast and Belarus – are indicative. Apart from the question of the number of participant troops – 12.700 or more  – for many in the Baltic States and Poland, the exercises were reminiscent of the Russian military exercises that morphed into a military intervention in Georgia (South Ossetia) in August 2008. Some made even reference to a statement of then Polish President Lech Kaczynski on 5th August 2008 in Tbilisi, in which he – in response to that Russian military intervention – stated: ‘Today, Georgia. Tomorrow Ukraine. The day after, the Baltic States – and later perhaps the time will come for my country, Poland !’ Concerns about Russian soldiers left over from the exercises invading – without military insignia – neighbouring areas (like what allegedly happened in Eastern Ukraine in 2014) were running high. It both reflected and added to the strong feelings of vulnerability in the area towards Russia in general and Putin in particular, especially after the Russian annexation of Crimea in March 2014.
The annexation of Crimea strongly intensified, in parts of the EU, the sensitivities about Putin’s Russia and the possible direct threat that it could represent to its eastern member states. The Crimean annexation was indeed more than a hybrid event . A hybrid event is itself already problematic, at least from the perspective of countries concerned about their territorial integrity and security stability as several cases (Georgia, Moldova, Ukraine) show. But a unilateral annexation directly pulls at one of the pillars of the European security system as built since the Helsinki Process of the 1970s, namely the principle that countries cannot unilaterally shift borders. Even if the Russian response to this is that NATO did the same with the creation of an independent Kosovo (which is not recognised as such by the Russian Federation), the annexation of Crimea showed that Putin was prepared to go far whenever he believed the strategic or even tactical situation permitted him to do so. Whether rightly or not, it creates fear and that fear clearly is affecting the feelings of direct insecurity in Poland, the Baltic States and along the EU eastern external borders in general.
But as indicated above, Zapad 2017 was perceived by many, as part of hybrid warfare, a notion developed by Valeri Gerasimov in February 2013. ‘In the twenty-first century’, he wrote, ‘the difference between times of peace and times of war disappear.’ Cyberwarfare, in all its dimensions (cyberattacks, propaganda, fake news) are all part of it. It is, as some have observed, a way for a weaker power to cope and to surpass a bigger one, and that is clearly the angle used by Gerasimov. In different ways – Estonia 2007, Georgia 2008, Ukraine 2014, Germany 2015, U.S. 2016 – this has become very visible.
NATO is specifically a target in this context and that effort has intensified since the decision to send troops to the Baltic States, Poland, Bulgaria and Romania after the Russian annexation of Crimea. Some see it as part of the Russian arsenal to complicate NATO’s ability to evoke article 5 of the Washington Treaty, the mutual security obligation of the Alliance. Propaganda may indeed lead to divergent pressures from the different public opinions in the 29 NATO member states, while the application of hybrid warfare makes it difficult to determine whether an attack covered by article 5 really took place and should therefore be replied to accordingly.
The Election of Donald Trump: The Straw that Broke the Camel’s Back?
On 6th July 2017, an interesting debate took place in the Netherlands’ Tweede Kamer, the lower house of the Dutch Parliament. It focused on the question of European defence, most particularly, the three scenarios developed by the European Commission with respect to such a defence . At a particular point, however, the debate briefly took a remarkable turn as MPs started to debate the exact role of Donald Trump’s election in the rapidly rising interest for plans about a European defence. Was it really Trump and his approach to NATO that caused this or was Trump just a peculiar expression of U.S. frustrations that already existed for quite some time? Some MPs believed it to be the former, others were convinced about the latter. European reluctance to invest more in their own defence fed U.S. frustrations and under Trump, the U.S. was just about to run out of patience. Had people forgotten how Bob Gates left the Pentagon in 2013 or how Obama expounded his frustrations in this regard in an interview with The Atlantic in March 2016 ? And what about the Asian Pivot? Is Arnaud Leparmentier right, when he writes that ‘European defence has returned on the political agenda since Trump’s election, a president who wants to accelerate America’s disengagement from Europe, an endeavour started by Obama .’ Is the U.S. – or for that matter U.S. public opinion – running out of willingness to guarantee European security? Are the tweets and statements by Donald Trump not misleading in this regard because they provide the impression that this is a “one-man-show”, some volatile expression from a narcissistic, myopic president who will be out of office anyway in little more than three or seven years. Yes, Trump has been unique in his criticism of the Europeans and their alleged lack of burden-sharing for their own security. The uniqueness is, however, not that much in the tweets but in the claim that NATO is “obsolete” and that the implementation of article 5 can be conditioned on European burden-sharing. Call it Trump’s art of dealing with Europe or with security in general with the effect of uncertainty that borders on panic. Timing matters as well. Questioning article 5 at a moment when Europe and European public opinion experience a multiple sense of insecurity inevitably raised the question whether the U.S. would be willing to guarantee European security when it really matters. In this sense, Trump’s notion of an obsolescent NATO provided the straw that broke the camel’s back on which Europe’s sense of security ultimately relied.
Europe’s Search for Solutions
According to Eurobarometer, in response to the growing power and influence of Russia, about 71 % of EU citizens would prefer joint action by the EU member states against only 19 % that would prefer individual action by their member state. The figures for the growing influence of China are more or less the same, as are the reactions to instability in the Arab/Muslim world . Support for a stronger Common Defence and Security Policy is similarly high, reaching levels of 75 % in the EU as a whole . These are vast majorities, a figure that is often used by those in favour of a more strongly integrated European defence and security policy. As remarkably as these figures may be, they have not really been influenced by the developments in and around Europe since 2014. Nor do they reflect a blind confidence towards the EU or what it is doing in respect to its external challenges. As found by Eurobarometer, 52 % think the EU’s actions to be inadequate when it comes to the EU’s external borders. 44 % believe this to be the case regarding the EU security and defence policy and 42 % regarding its foreign policy. At the same time and after a dip in 2016, confidence in NATO has increased to levels comparable to the preference for joint EU actions. Outliers here are Poland and the Netherlands with very high levels of confidence in NATO, as well as France and Spain with relatively low levels . Clearly, among European public opinion, there is no perception that there is, or has to be, an opposition between NATO on the one hand and a stronger Common Security and Defence Policy (CSDP) on the other hand.
Political responses to the Commission’s Reflection paper on the future of European defence  reach out to a stronger CSDP. There generally is support for stronger European cooperation in that area but not for stronger European integration in a supranational sense. The Commission’s proposal on EU battalions and a European military headquarter is supported as well, but not always in the sense of the creation of a European army. The support is broader when it comes to a European defence market. Many realise that European countries’ limited resources on defence can be spent more efficiently and drawing from an integrated defence market may promote interoperability as well. At the same time, on the side of Europe’s left there is general scepticism about the need to invest in new military structures or in defence in general.
The stars seem aligned for a European defence policy to move forward, at least to make a qualitative leap. The overarching sense of instability and vulnerability in Europe and the feeling that U.S. commitment to European security cannot be taken for granted much longer have led European leaders to consider such a leap more than before. But that doesn’t mean that the elements that previously drove European debates on this issue have disappeared. The relationship with NATO – and concerns that a stronger European defence could possibly undermine it – is prevalent in this context, as is the concern about the financial costs and the creation of a myriad of mutually competing security structures. And as the past has shown, European stars, as aligned as they may be today, may not be that aligned anymore tomorrow. Indeed, whatever the volatility of the European security environment may be today, whether the EU will be able to provide a credible and durable response remains to be seen.
 Cf. T. BARBER (2017), ‘Europe Starts to Think the Unthinkable: Breaking Up’, in: Financial Times, 2nd March 2017; M-T. STRAGGIOTTI (2017), ‘Selon les medias étrangers, le sort de l’Europe dépend des électeurs français’, in: Boulevard Extérieur, 22nd April 2017; J. AUTHERS (2017), ‘Authors’ Note: State of the (European) Union’, in: Financial Times, 1st March 2017.
 F. VENTURINI, in: Corriere della Sera, 8th May 2017.
 Cf. G. BLUME (2017), ‘Europa kann aufatmen’, in: Die Zeit, 24th April 2017; F. FEDERL (2017), ‘Ouf!’, in: Die Zeit, 7th May, 2017; F. VENTURINI (2017), ‘Bruxelles respira (ma non basterà)’, in: Corriere della Sera, 8th May 2017; V. POP (2017), ‘Win Slows Anti-EU Movement’, in: The Wall Street Journal, 8th May 2017, p. A8; V. POP (2017), ‘Win Heartens Europe Leaders’, in: The Wall Street Journal, 8th May 2017, p. A8.
 Review & Outlook, ‘Europe’s French Reprieve’, in: The Wall Street Journal, 8th May 2017, p. A18.
 R. BOLLMANN (2017), ‘Kohls späte Erbin. Angela Merkel stellt die Weichen für eine Vertiefung der EU’, in: Internationale Politik, Juli/August 2017, p. 77. (EN: Contributing to the success of the newly elected French president is an integral part of Merkel’s European plan, however without neglecting Germany’s own interests. No one can be in favour of a right wing Marine Le Pen as president of the French neighbour in five years, as voices spread around Merkel.).
 Paolo Gentiloni, quoted in: La Stampa, 30th June 2017. (EN: The migration flows don’t stop. If you don’t help us, there is a risk that populists might win the next elections in Italy. (...) This is a message from a country which does not violate the rules but who is under pressure and asks for hands on contribution from its European colleagues.).
 EUROPEAN COMMISSION (2017), EU-Turkey Statement. One Year On.
 Cf. the claim made by Turkish EU affairs minister Omer Celik, that the EU was not keeping its promises with respect to the 3 billion euro and visa waiving for Turkish nationals, and that several member states – particularly Germany – were ‘using the EU negotiating process [on Turkey’s EU accession] as a way to blackmail Turkey’ (Financial Times, 15th September 2017).
 Cf. Financial Times, 15th September 2017.
 Turkey officially applied for EU membership on 14th April 1987.
 Cf. ‘German Turks unsettled as shadow of Erdogan looms over elections’, in: Financial Times, 25th August 2017.
 NATO/OTAN (2017), ‘Defence Expenditure of NATO Countries (2010-2017)’, in: NATO Press Release PR/CP(2017)111, 29th June 2017.
 Whenever a military exercise reaches 13.000, foreign observers (in this case, NATO observer) have to be invited and granted access to them, following commitments under the confidence- and security-building measures (CSBMs) of the OSCE.
 T.K. KOWALIK, D.P. JANKOWSKI (2017), ‘The Dangerous Tool of Russian Military Exercises’, in: Europe’s Edge, Center for European Policy Analysis, 9th May 2017.
 With ‘hybrid event’, reference is made to the notion of ‘hybrid war’, a notion launched by Russian general Valeri Gerasimov, chief of staff of the Russian armed forces, in the Russian military journal VPK edition of February 27, 2013 (see: В. Герасимов (2013), ‘Ценноть науки в предвидении’, in: Военно-Промышленный Курьер ВПК:, n° 8 (476), 27th February– 4th March 2013, p. 1 & 2). Hybrid war refers to the fact that the difference between war and peace is not clear-cut anymore and that waging war can happen without doing it through a traditional military attack. The non-traditional is the ‘non-contact’ approach to military operations, or, as Gerasimov indicated himself in the article: ‘бесконтактное воздействие на противника становится главным способом достижения целей боя и операции’ (‘Non-contact influence towards the opponent becomes the most important approach to globally succeed in the battlefield and in military operations’).
 TWEEDE KAMER DER STATEN-GENERAAL (2017), Debat over de plannen voor een Europese defensie, Tweede Kamer, 97e vergadering, 6th July 2017.
 J. GOLDBERG (2016), ‘The Obama Doctrine. The U.S. President Talks Through his Hardest Decisions about America’s Role in the World’, in: The Atlantic, April 2016 Issue.
 A. LEPARMENTIER (2017), ‘Tailler l’Europe comme un rosier’, in: Le Monde, 30th March 2017, p. 27.
 EUROPEAN PARLIAMENT (2017), ‘Two Years until the European Elections’, in: Special Eurobarometer for the European Parliament, April 2017, pp. 18-22.
 EUROPEAN COMMISSION (2017), ‘Public Opinion in the European Union’, in: Standard Eurobarometer, n° 87, Fieldwork May 2017, p. 176.
 B. STOKES (2017), NATO’s Image Improves on Both Sides of the Atlantic, Pew Research Center, May 2017, p. 8.
 EUROPEAN COMMISSION (2017), Reflection Paper on the Future of European Defence, Brussels, European Commission, COM (2017)315, 7th June 2017.