Policy Brief

Dec 19, 2019

No Time to Lose for the EU

Overcoming the Accession Stalemate in the Western Balkans

EU enlargement policy toward the Western Balkans has never been as contested as today. French President Emmanuel Macron has made reform of the EU accession process a precondition to opening membership talks with Albania and North Macedonia. While the current stalemate severely undermines the EU’s reform and stabilization agenda in the region, it also offers an opportunity for an overhaul of the accession process, which is long overdue.




  • In March 2020, the European Council should give the green light to accession talks with Albania and North Macedonia while simultaneously spelling out guiding principles for reform.
  • Dividing the accession process into seven successive stages, as suggested by a recent non-paper from France, bears the risk of slowing it to stalemate and losing EU leverage on candidate countries.
  • Reform of the EU accession process should deliver a revision of monitoring and assessment mechanisms, an increase in the cost of non-reform for political leaders in the region, and a raised scale of EU action to achieve a systematic impact on the ground.
  • The initial Conference on the Future of Europe in 2020 would be an ideal occasion for inviting political and civil society representatives from the Western Balkans to take an active part and reinvigorate political dialogue about their long-term perspectives in the EU.

The EU’s starting position on enlargement policy in its new institutional cycle is tricky. How can EU actors overcome the stalemate that the accession process is currently experiencing? How should they respond to the recently circulated non-paper specifying French demands for reform? Any redesign of the current accession process will need to address three central challenges that are spelled out below along with concrete measures for the EU to finally pull its weight in the Western Balkans.

Contentions on Enlargement

When Athens and Skopje resolved their 27-year name dispute by reaching the Prespa Agreement in June 2018, hopes were high that the rebaptized “Republic of North Macedonia” would finally be able to start EU accession talks. Indeed, for the first time since the European Commission recommended opening negotiations ten years ago, Greece lifted its veto. But it was France that denied its approval and continued to do so at the latest European Council meeting on October 17–18, 2019. This, in turn, incited strong reactions by both EU institutions[1] and numerous member states – among them Germany, Italy, and Poland – showing that the camp of supporters of the accession process is still large and vocal. Outgoing Commission President Jean-Claude Juncker went as far as to call the rejection of North Macedonia, as well as its neighbor Albania, “a grave historic mistake.”[2]

The stalemate resulting from the October summit is the latest and most flagrant expression of a fading consensus on whether, how, and how fast to integrate aspiring members. It fundamentally undermines previous commitments and initiatives to reinvigorate the EU integration of the Western Balkans, such as the Berlin Process, under which regular summits have been held since 2014, or the EU’s new enlargement strategy, which was launched in February 2018.[3] At stake is no less than the question of whether membership for the Western Balkans is still on the table – and thus also the EU’s credibility and leverage in the region.

On a more positive note, President Emmanuel Macron’s demand for an overhaul of current accession methodology, which accompanied France’s rejection of fresh membership talks, has fueled EU debate on reform. This reform is long overdue as it has become evident that the accession process, as it is currently designed and implemented, has not delivered on its promise to foster democracy and prosperity throughout the region. At the same time, fundamental bilateral disputes and state-building issues still linger. A reform is thus vital for ending the current blockade of the accession process and erasing its shortcomings.

The Accession Process on Ice

Blockades of EU accession candidates from the Western Balkans have a long tradition. In the past, such blockades have originated from bilateral disputes between member states and accession aspirants – for example, between Slovenia and Croatia and, after the latter joined the EU, Croatia and Serbia. They have also stemmed from a strict interpretation of accession conditionality, such as the Netherlands’ insistence on Serbia’s cooperation with the Hague Tribunal. The current stalemate, however, is qualitatively different. At the October Council, the most principled opposition to the opening of accession negotiations with two additional candidates was voiced by France. Regarding Albania, France was backed by Denmark and the Netherlands, but it stood alone with its veto against North Macedonia. President Macron turned down all compromise solutions, including a German proposal that would have opted for a conditioned opening of accession negotiations.

First, this latest episode revealed the blatant lack of a common understanding among EU actors about the requirements for reforms the two Balkan countries were told to make and whether or not they had been met. In September 2019, the German Bundestag followed the Commission’s recommendation to open accession talks with North Macedonia and Albania – only after it formulated a number of conditions for the latter that surpassed previous EU requirements.[4] The Dutch parliament came to the conclusion that North Macedonia, but not Albania, was ripe for opening negotiations, while France abruptly voiced concerns at the October Council that neither country was prepared enough. This cacophony of assessments raises serious questions about the objectivity of the process.

Second, Paris has made the continuation of the enlargement process contingent on prior reform of the EU. At the October Council, France made it clear that it wants to see a change in the modalities of the accession process before membership talks can be opened with prospective members. Consequently, the actual admission of new entrants could only take place once the EU as a whole has been reformed. France’s two comprehensive demands are addressed to member states, not candidate countries. Therefore, it may take months or – in the case of a far-reaching reform of the workings of the Union – even years to meet them.

Third, there are strong indications that domestic motives – specifically uneasiness on migration – are driving states that are skeptical of enlargement. National populists should not be given any ammunition for stirring anti-migration and anti-EU sentiment before key elections. It is thus no coincidence that France insisted on postponing the presentation of 2019’s enlargement package until after European elections. Similarly, in May this year, the Dutch government asked the European Commission to suspend visa-free travel for Albanian citizens after parliament voted in favor of such a measure.

These concerns are related neither to a candidate country nor its bilateral relations, but rather to the domestic affairs of member states and the future of the EU integration project. When considering accession, it is frequently stressed that hopefuls should advance “on the basis of their own merits,” but such developments effectively suspend this formula. This not only affects Albania and North Macedonia – where Prime Minister Zoran Zaev already called early parliamentary elections – but also the region as a whole. The prospect of not advancing on their EU path, regardless of their achievements, is likely to undermine the candidate countries’ reform efforts, including the EU-mediated dialogue between Kosovo and Serbia, the implementation of the Prespa Agreement, and the fight against state capture across the region.

It would be ill-advised to assert that France threw a wrench into the machinery of EU integration that was otherwise functioning perfectly. Still, the current stalemate risks making things worse as it appears to be leading the EU to deliberately and unnecessarily renounce its capacity to shape developments in the region. EU leaders are well aware that they face fierce competition by Russia, China, Turkey, and the Gulf states, which have stepped up their political and economic, as well as their cultural and religious presence in the region. Thus, then-designated European Commission President Ursula von der Leyen noted in her mission letter to the then-designated Commissioner for Neighborhood and Enlargement that “external influence in the region has been growing significantly.”[5] To prevent the Western Balkans from further drifting away from the EU’s fold, it is therefore crucial to overcome the current blockade and, at the same time, address the dysfunctionalities of the accession process.

Reforming Enlargement – or Putting it on Hold?

The French veto at the October Council – accompanied by president Macron’s request to overhaul the current methodology of accession – has catapulted enlargement policy and debate on its reform to a top spot on the EU’s agenda. France specified its demands in a short non-paper distributed to EU partners in November 2019.[6] At its core, it proposes to replace the 35 negotiating chapters with seven successive stages along thematic policy blocs, in which candidate countries would gradually be included. The non-paper contains a number of elements that could considerably advance the integration of the Western Balkans into the EU, in particular a gradual inclusion in sectoral policies even before accession,[7] an increase of financial means, and the demand for reversibility in cases of backsliding. Other principles, such as the respect of precise criteria and the front-loading of issues related to the rule of law, have already been part of the current enlargement strategy, but – as shown below – have not always been translated from paper into practice.

France’s proposal, however, also triggers many questions about practical implementation and its effects, for example: How advanced would reforms related to rule of law need to be in the first stage of accession negotiations before a country could move to the next level? What benefits would be offered to candidates in the initial four stages? And why would access to the single market only follow in a fifth – rather late – stage in the accession process? Also, which solution should be applied to Montenegro and Serbia, countries which already find themselves in the midst of “traditional” membership talks structured by the 35 chapters? The most important caveat to the French model, however, concerns its consecutive character. Accession preparations in a given area often need many years to be accomplished. Treating each area one after the other – rather than conducting them in parallel – might prolong negotiations to an extent that keeps eventual EU accession out of sight for candidate countries.[8]

With the French veto overshadowing the reform process, the pro-enlargement bloc among member states has an interest in ending the current stalemate as soon as possible. Paris, however, will most likely insist on not opening accession negotiations with any further candidates before a new methodology has been introduced. The process, thus, faces two risks. On the one hand, disagreement among member states on the path to reform could prolong the detrimental blockade of the Western Balkans’ perspective for entering the EU. On the other, a hasty overhaul of the highly complex accession procedure might not lead to the reduction in dysfunctionality that is sought, but rather its increase. The ball is now in the court of the European Commission. It is expected to present its own proposal for a reform of the accession process in January 2020, which will then serve as a basis for further discussion.

Three Key Challenges to Reforming the Accession Process

Despite happening under unfavorable circumstances, an overhaul of the accession process constitutes a unique opportunity to eradicate a number of substantial shortcomings that have hampered its effectiveness. Three paths for reform would allow the EU to better pull its weight in the Western Balkans. Rather than offering one specific model, the proposed measures point to a number of challenges that need to be addressed in any redesign of the accession process.

The discussion of reform proposals departs from the assumption that the goal of a gradual accession process needs to be full membership – provided that EU conditionality is genuinely fulfilled by candidate countries. In the region, a withdrawal of the accession perspective would be clearly perceived as a rejection and renouncement of the EU’s previous commitments. Any lighter form of association would considerably decrease the EU’s leverage on reform, in particular with regard to democratic standards and the rule of law. It would also hardly be enough to counter the influence of other foreign actors and may turn out to be detrimental to long-term stabilization in the region. Any makeover of the accession process thus needs to be based on a credible membership perspective.

Improve Monitoring and Assessment Mechanisms

A fundamental stumbling block that has impeded the accession process for years is the lack of trust expressed by member states in the assessments delivered by the European Commission. Member states favoring strict conditionality have repeatedly contested the criteria for (potential) candidates to move to the next level in the accession process and their actual fulfilment. This has already been the case in the opening of accession talks with Montenegro and Serbia, and, more recently, as shown above, with Albania and North Macedonia. In addition, although the European Commission concluded in July 2018 that Kosovo met all benchmarks set out in its Visa Liberalization Roadmap, the Council has not yet granted the long-awaited visa free travel to Kosovar citizens.

A similar problem arises with regard to the annual country reports issued by the European Commission. Across EU capitals, they are perceived to be politicized, often painting a too rosy or blurred picture of events on the ground. The reports do not allow citizens from the region to grasp at a glance whether their government performed well in bringing the country closer to the EU. Due to their vague and coded language, they require “interpretation” by government officials or experts, which, in turn, leaves plenty of room to distort the picture. Thus, there is a fundamental need to reform the EU reporting system in order to deliver an unambiguous and transparent overall assessment. The Council and the Commission need to prioritize clarifying how the latter can undertake future assessments of candidates’ progress in a way that allows all member states to rally behind them. A greater role in this could also fall to the European Parliament, for example by linking the work of rapporteurs to European Commission reports.

In addition, analysts from Montenegro and Serbia underline that accession talks on rule of law chapters lack efficient monitoring and clear guidelines. This is despite the fact that the EU introduced a detailed rule of law mechanism in 2012 that provides for opening chapter 23 on judiciary and fundamental rights and chapter 24 on justice, freedom, and security at the very beginning of accession negotiations. The political front-loading of reforms related to the rule of law should consequently allow for the establishment of a track-record of implementation. In practice, however, action plans that were supposed to be “living documents” stimulating the reform process have not been subject to regular updates, thus outliving current reform needs and leading to very selective implementation.[9] The “new approach” on the rule of law still allows the governments of the Western Balkans to put thorny measures on the backburner. It is thus high time to establish a monitoring and benchmarking system with clear priorities and timelines. This would also facilitate applying the overall balance clause in case of a severe deviation. The application of the clause would lead to the freezing of negotiations on other chapters if progress under chapters 23 and 24 significantly lags behind.

Enhance the Cost of Non-Reform

The accession process in its current design rewards politicians for maintaining the status quo. It brings a large number of benefits to ruling elites in the Western Balkans by opening economic opportunities and the constant inflow of pre-accession funds. Politicians obtain positive media coverage when shaking hands with their counterparts from Brussels and EU capitals and can impress voters with the promise of EU accession, which is still – in spite of everything – attractive. Political leaders across the region enjoy these advantages, regardless of

whether they conduct genuine reforms or are merely pretending to. What is more, the EU has turned a blind eye to backsliding on democratic standards and the rule of law in many instances in recent years. The losers here are the citizens of the Western Balkans, for whom – as the current mass exodus and street protests show – living conditions are becoming less and less bearable.

Holding decision-makers accountable for preventing reform requires inflicting a cost on them that should be as painstakingly high as that for

ordinary citizens. One way to achieve this would be to make the disbursement of pre-accession funds strongly dependent on a country’s actual performance in key areas of the integration process – for example, on the rule of law and fundamental rights, on good relations with its neighbors, and

socio-economic development. The current proposal of an IPA III regulation is a first positive step in this direction[10]. To make it more effective, it also needs to contain a robust suspension clause that allows for the (temporary) withdrawal of funds in cases of backsliding or a prolonged standstill of reforms.

Second, the EU needs a clear and outspoken form of communication about a country’s performance in approaching (or drifting away) from the accession criteria. As discussed above, current EU country reports do not live up to this task. In addition to regular reporting, Brussels needs to speak up every time the violation of fundamental principles gives rise to concern. This applies not only to infringements of democratic standards, the rule of law, and fundamental rights, but also to agitations and provocations against neighbors or other national groups within a given country. While interventions by member states might be perceived as biased, the European Commission would be the right body to voice criticism based on objective criteria that apply to all six Western Balkan candidates. In practical terms, such an approach would be an ultimate challenge for the new Commissioner for Neighborhood and Enlargement Olivér Várhelyi to prove his independence. He was nominated by Hungary, which itself has been under criticism for hollowing out rule of law standards and provides political asylum to former Macedonian Prime Minister Nikola Gruevski who fled his country in November 2018 to escape a jail sentence for corruption.

Move from Symbolic to Systematic Impact

Monitoring reforms and sanctioning their non-implementation is only one side of the coin. The other is the need to create both comprehensive and concrete incentives. Having in mind that actual accession is a medium- to long-term goal, accession candidates already need to be tied more closely to EU institutions, programs, and standards now. This includes – but does not rely solely upon – more financial resources.

A special role could fall to the yearly Western Balkans summits, better known as the Berlin Process. It reached its goal insofar as it gave new momentum and visibility to the EU enlargement agenda, particularly to issues of regional cooperation. Nevertheless, after six rounds of high-level summits, interim stocktaking suggests that in many areas the outcomes remain at a symbolic level, instead of achieving real impact on the ground. Take, for instance, the establishment of the Regional Youth Cooperation Office (RYCO), which is frequently praised as one of the most important achievements of the Berlin Process. While the very existence of RYCO is a success in itself, its annual budget amounts to no more than two million euros to support projects in six countries. With these limited resources, the number of young people that youth exchange activities throughout the region can effectively reach remains small. Other matters – such as the establishment of a common economic area, the resolution of bilateral disputes, reconciliation, and the issue of missing persons – have floundered. In a new enlargement architecture, the Berlin Process could be embedded in a more institutionalized setting that provides continuity above the yearly changing chairs. It would cover all areas of regional cooperation for which bilateral negotiations between the EU and accession aspirants do not provide a platform. This would also ensure that thorny issues remain on the agenda and do not have to give way to ever new priorities.

Given the low levels of economic development and strained budgetary resources, there is a need to already step up funding considerably within the pre-accession period. Currently, there is a blatant gap between the financial support given to member states and accession candidates. For example, under the instrument for pre-accession (IPA II), the six countries of the Western Balkans have received 3.9 billion euros from 2014 to 2020. During the same period, the new member state Croatia alone has access to 10.7 billion euros of structural funds and has encountered serious problems in absorbing this sudden cash inflow. To achieve a gradual increase in funding and better support cost-intensive EU approximation, experts have repeatedly proposed opening structural funds to the Western Balkans.[11] Ideally, the provisions to include the region in the structural funds scheme would be integrated in current negotiations on the Multiannual Financial Framework for 2021–2027. If this fails, funds could also be contributed by member states supportive of the Western Balkans’ accession agenda, for instance in the frame of the Berlin Process.

Addressing the enormous brain drain that currently affects the region is another issue that may prove to be a game changer. In 2018 alone, 230,000 citizens from the Western Balkans obtained first permits of residence within the EU. Among them, around 62,000 Albanians left their country for the EU, which is roughly two percent of the population.[12] The current exodus not only negatively affects the economies of the region, but it also deprives it of young, highly educated, and open-minded people who could sustainably anchor the conducted reforms within state institutions and society. While mobility is currently a one-way street that leads from the region to the EU, specific programs promoting circular migration[13] could encourage the return of a highly skilled workforce.

More imminently, the Conference on the Future of Europe announced by Commission President von der Leyen to be launched in 2020 would be an ideal occasion to invite representatives, including civil society actors, from all six (potential) candidate countries.[14] EU leaders could thus build on the example of the Convention on the Future of Europe in the early 2000s that included the prospective member states from Central and Eastern Europe. This would give members-to-be the chance to not only take, but also shape the outcome of discussions. An invitation would be even more appropriate as the conference title implies that the future not only of the EU, but also of Europe as a whole will be at the center of discussion.

Escaping the Dilemma

With enlargement skepticism paralyzing the accession process and multiple crises facing the EU from within, it may sound tempting and even reasonable to slow down or suspend the integration of the Western Balkans into the EU. As French President Macron put it, the EU needs to bring its own house in order before inviting new friends.[15] However, time matters. Reforming the EU and preparing candidates for their eventual accession are two endeavors that can run in parallel and are even required to do so. This is not only due to the large amount of time that both processes need. Addressing the serious consequences of the roll-back of domestic reform, open state-building issues, and disillusioned citizens – not to mention of external actors yielding to expand their own political and economic influence – cannot wait until the EU is again ready to invest attention and resources to the region.

Germany should clearly signal that an end to the current blockade and a reconfirmation of a credible EU perspective for the Western Balkans is one of its core European policy interests: The EU’s broader reputation as an international partner is at stake if it cannot even fulfil the ambition of reliably shaping relations with (potential) candidate countries in its immediate neighborhood. In fact, a number of aspects of the French reform agenda – in particular the need for stringent and precise accession criteria, the political front-loading of issues related to the rule of law, and the creation of tangible benefits for citizens in the Western Balkans – resonate well with long-standing German demands and could thus serve as common ground for reform. However, it needs to be ensured that a redesigned accession conditionality serves as an effective tool for transformation and not as a tool for preventing the integration of the Western Balkans into the EU. To this end, it will be crucial to link it to attractive (financial) incentives and an early integration of accession aspirants in EU structures.

To start with, in March 2020, the European Council could give the green light to accession talks with Albania and North Macedonia, which are sure to be lengthy. At the same time, it could spell out initial guidelines for a makeover of the accession process that could subsequently be refined at the EU-Western Balkans summit in May 2020. EU member states could thus escape the dilemma of having to choose between a hasty reform and a prolonged blockade of the accession process, while simultaneously sending a strong signal to candidate countries that their achievements are being honored.


[1]          See, for instance, the joint letter by Presidents Donald Tusk, David Sassoli, Jean-Claude Juncker, and President-Elect Ursula von der Leyen on the opening of accession talks with North Macedonia and Albania from October 3, 2019: https://www.consilium.europa.eu//media/40906/20191003-accession-talks-appeal-signed.pdf?utm_source=dsms-auto&utm_medium=email&utm_campaign=Joint+letter+by+Presidents+Tusk%2c+Sassoli%2c+Juncker+and+President-elect+von+der+Leyen+on+the+opening+of+accession+talks+with+North+Macedonia+and+Albania (accessed November 3, 2019).

[2]         Andrew Gray, “Juncker: EU’s North Macedonia, Albania Rebuff is ‘Historic Mistake,’” Politico, October 18, 2019:

https://www.politico.eu/article/jean-claude-juncker-eu-north-macedonia-albania-rebuff-historic-mistake/ (accessed November 3, 2019).

[3]          European Commission, “A credible enlargement perspective for and enhanced EU engagement with the Western Balkans,” COM(2018) 65 final, Strasbourg, February 6, 2018: https://ec.europa.eu/commission/sites/beta-political/files/communication-credible-enlargement-perspective-western-balkans_en.pdf (accessed November 3, 2019).

[4]         German Bundestag, “Einvernehmensherstellung von Bundestag und Bundesregierung zum Beitrittsantrag der Republik Albanien zur Europäischen Union und zur Empfehlung von Europäischer Kommission und Hoher Vertreterin vom 29. Mai 2019 zur Aufnahme von Beitrittsverhandlungen,” Drucksache 19/13509, September 21, 2019: http://dip21.bundestag.de/dip21/btd/19/135/1913509.pdf (accessed November 12, 2019).

[5]          European Commission, “Mission letter by Ursula von der Leyen to László Trócsányi, Commissioner-designate for Neighbourhood and Enlargement,” Brussels, September 10, 2019: https://ec.europa.eu/commission/sites/beta-political/files/mission-letter-laszlo-trocsanyi_en.pdf (accessed November 3, 2019).

[6]         “Non-paper: Reforming the European Union accession process,” November 2019: https://www.politico.eu/wp-content/uploads/2019/11/Enlargement-nonpaper.pdf (accessed November 26, 2019).

[7]          The concept of sectoral integration reflected in the French non-paper had recently been suggested by Milica Delevic and Tena Prelec. See: Milica Delevic and Tena Prelec, “Flatter and faster: New Western Balkans pathways to the EU,” Views from the Council, European Council on Foreign Relations, October 24, 2019: https://www.ecfr.eu/article/commentary_flatter_and_faster_new_western_balkans_pathways_to_the_eu (accessed November 3, 2019).

[8]         This also appears to be a major concern voiced by a joint non-paper from Austria, the Czech Republic, Estonia, Italy, Latvia, Lithuania, Malta, Poland, and Slovenia that, in reaction to the French non-paper, requests “it should be possible to open groups of chapters in parallel and not consecutively.” See: Barigazzi, Jacopo, “9 EU countries push back on French enlargement revamp,” Politico, December 13, 2019: https://www.politico.eu/article/eu-enlargement-reform-pushback/?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=RSS_Syndication (accessed December 16, 2019).

[9]         Jovana Marovic, Tena Prelec, and Marko Kmezic, “Strengthening the Rule of Law in the Western Balkans: Call for a Revolution against Particularism,” Policy Study, Balkans in Europe Policy Advisory Group, January 2019: https://biepag.eu/strengthening-the-rule-of-law-in-the-western-balkans-call-for-a-revolution-against-particularism/ (accessed November 3, 2019).

[10]        European Commission, “Proposal for a regulation of the European Parliament and of the Council establishing the Instrument for Pre-accession Assistance (IPA III),” COM(2018) 465 final, Brussels, June 14, 2018.

[11]         See, for instance, these two texts: Matteo Bonomi and Dušan Reljić, “The EU and the Western Balkans: So Near and Yet So Far,” SWP Comment 53 (December 2017), p. 4: https://www.swp-berlin.org/fileadmin/contents/products/comments/2017C53_rlc_Bonomi.pdf (accessed November 3, 2019);

Pierre Mirel, “European Union-Western Balkans: For a Revised Membership Negotiation Framework,” European Issue n°529, Fondation Robert Schuman (September 30, 2019): https://www.robert-schuman.eu/en/european-issues/0529-european-union-western-balkans-for-a-revised-membership-negotiation-framework (accessed November 3, 2019).

[12]        Calculations based on the Eurostat database “First permits by reason, length of validity, and citizenship,” last updated October 28, 2019 (accessed November 11, 2019).

[13]         See, for instance: Alida Vračić, “Luck like the Irish: How emigration can be good for the Western Balkans,” ECFR Policy Brief, January 31, 2019: https://www.ecfr.eu/publications/summary/luck_like_the_irish_how_emigration_can_be_good_for_the_western_balkans (accessed November 3, 2019).

[14]        Proposal discussed at the Western Balkans Reflection Forum, Zagreb, October 16, 2019. The demand also figures in the joint non-paper circulated by nine member states in December 2019. See: Barigazzi, Jacopo, “9 EU countries push back on French enlargement revamp,” see note 8.

[15]         Rym Momtaz and Andrew Gray, “Macron urges reform of ‘bizarre’ system for EU hopefuls,” Politico, October 16, 2019: https://www.politico.eu/article/macron-urges-reform-of-bizarre-system-for-eu-hopefuls/ (accessed November 3, 2019).


Bibliographic data

Töglhofer, Theresia. “No Time to Lose for the EU.” December 2019.

DGAP Policy Brief No. 8, December 19, 2019, 9 pp.

Themen & Regionen