What were the main political and economic consequences of the 2004 and 2007 enlargements for the new member states and the EU?

 Aseel Azizieh 

Study: July 2026

What were the main political and economic consequences of the 2004 and 2007 enlargements for  the new member states and the EU? 

Abstract 

This essay looks at the political and economic consequences and efforts of the 2004 and 2007 EU enlargements for both the new member states and the EU itself. After reading many academic studies, I found that the enlargement helped these countries grow economically. Their GDP per capita went up, productivity improved, and they started catching up with Western European income levels. But not everything went smoothly. Social progress didn’t keep up with economic growth, and lots of people moved to Western Europe for work, which created both benefits and problems. The political side is more worrying. Even though the European Union pushed countries to become more democratic before they joined, places like Hungary and Poland have been moving backwards on democracy after joining. This shows that the European Union’s power to change countries doesn’t last forever. For the EU, the enlargement made Europe more stable and secure, but it also made decision- making harder, put pressure on the budget, and created a rule of law crisis that makes the European Union look less credible when it tells other countries to follow democratic rules. These lessons matter a lot right now because the EU is getting ready to enlarge again with Ukraine, Moldova, Georgia, and the Western Balkans. 

Keywords:

EU enlargement, 2004/2007 enlargement, Big Bang enlargement, democratic backsliding, economic convergence, labour migration, rule of law, European Union, Central and Eastern Europe, conditionality, geopolitical enlargement. 

 Introduction The Big Bang That Changed Europe 

Twenty years ago, something extraordinary happened. In 2004 and 2007 , the European union welcomed 12 a new member states, ten in 2004 and two more and 2007, this Big Bang enlargement was the largest in the European Union history, bringing the countries that had spent decades behind the iron carton, a long awaited return to Europe after the fall of communism. (Anghel & Jones, 2024, p. 2 ).

But today, looking back at the picture is much more complicated. The enlargement had profound consequences, some positive, some deeply troubling . It brought economic growth and democratic reforms, but it also created new dependencies, fueled migration, and in some countries led to democratic backsliding. The European Union itself was transformed, becoming more diverse, but also more difficult to govern. As Schimmelfening (2024, p.79) argues, another major enlargement this time, including Ukraine, Moldova, Georgia, and the Western Balkans.

This essay examines the main political and economic consequences of the 2004 and 2007 enlargement felt for the new members date and then for the European Union itself.

The research question 

The question: What were the main political and economic consequences of the 2004 and 2007 engorgement for (a ) new member states and (b) the European Union? It is important for several reasons: First it helps us assist whether enlargement actually delivered on its promises , second it helps identify what went wrong and why and it offers lessons for the European Union’s next enlargement, which is already underway.

However, as Vukov (2024, p. 3060) notes , the literature on the 2004 enlargement as fragmented one group of schoolers studies the accession process and how the European Union in fall it condition another group focuses on economic development and market integration for the European Union, but there is a shortage of integrated comparative research that brings politics and economics together this is saying and to bread that gap by synthesizing findings of multiple studies with 2004 enlargement is also seen as a code behind many challenges the European Union faces today.

What were the main political and economic consequences of the 2004 and 2007 enlargements for  the new member states and the EU? 

Part (a) What Consequences for the New Member State? 

Literature Review: Economic Growth and Convergence 

The most widely recognized consequence of enlargement for the new member states  is economic growth. When the eight Central and Eastern European countries (Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Slovakia, and Slovenia plus Cyprus and Malta in 2004, and Bulgaria and Romania in 2007) joined the European Union, very well significantly poorer than the European Union average. The hope was that European Union membership would help them catch up.

Evidence from quantitative studies largely confirmed this hop. Grassi (2024, p. 1), using the sensitive control method (SCM) Synthetic Control Method , a statistical technique that creates a counterfactual virgin of a country to estimate what would have happened without European Union membership, found that by 2019, the new members  The Gross Domestic Product (GDP) per capita was 32% higher than their counterfactual. Their total factor productivity (TFP) grew at three times the rate of the European Union 15 Grassi (2024, p. 1) describes this as an “European Union miracle” where 75 million people reach high income status. 

Similarly, Hagemejer, Michalek, and Svatko (2021, p. 134) found that European Union membership has a significant positive impact on GDP per capita in new member states . For 5 of the 10 countries analyzed the difference against the counter factual was at least 30%. The gains from membership increased over time. More than doubling between the sixth and twelfth years after accession.  (Hagemejer, Michalek, and Svatko, 2021, p. 135). The authors  also found that countries entering with a relatively high level of development, such as the Czech Republic and Slovenia, experienced smaller gains.  (Hagemejer, Michalek, and Svatko, 2021, p. 135)

Próchniak and Rapacki (2024, p. 5) confirmed that European Union membership brought the economies of new and old member states closer together, with economic growth in the new member states being higher than in the rest of the European Union. They found that income inequality between old and new member states narrowed over time, with convergence particularly strong in Bulgaria, Romania, Poland, and Lithuania. (Próchniak & Rapacki, 2024, p. 12) 

The Ifo Institute (2024, p. 105) predicted before enlargement that new member states would benefit from trade gains and continued capital inflows, accelerating economic growth. However, they also warned that catching up with European Union 15 would take decades. (Ifo Institute, 2024, p. 108).

Labour migration, and liquid migration

One of the most visible social consequences of enlargement was large scale Labour for migration between 2004 and 2014. The total number of nationals from new member states residing in old member states increased from 1.1 million to 6.1 million, a more than fivefold increase (Engbersen, 2018, p. 63).

Godfried Engbersen and Erik Snel (2013, p. 25) describe this as liquid migration, a temporary, circular, and unpredictable movement, rather than permanent settlement. This concept captures how migration patterns became more flexible and individualized. Engbersen (2018, p. 64) identifies six key characteristics of liquid migration: temporality of stay, labour motivation, legal regular status, unpredictability of destinations, individualized family strategies, and a migratory habitus of intentional unpredictability.

The main destination countries were the United Kingdom, Ireland, Germany, Austria Italy Spain and the Netherlands (Engbersen 2018, p. 64). The scale of migration like Poland was enormous according to Glorius (2013, p. 12), several new groups of migrants emerged, particularly young people without January obligations or clear future plans. 

What were the consequences? For the new member states migration brought two things. First, “remittance “ money sent home by migrants which supported families and local economics. Second, “labour shortage “ in certain sectors. Some researchers also worried about “brain drain “ as skilled workers moved West. However, the evidence is mixed.  Some migrants return with  new skills. And many engaged in circular migration, going back and forth rather than settling permanently (Engbersen & Snel, 2013, p. 38).

Democracy and the rule of law

If economic growth was the success story, democracy is the cautionary tale. The Copenhagen criteria established in 1993 required candidate countries to have a table in institutions guaranteeing democracy, the role of law, human rights and respect for minorities.  During the accession process, The European Union used conditionality offering membership in exchange for reforms to push countries toward these standards. 

But after accession, the European Union’s leverage diminished dramatically. As Dawson, Herman, and Ananda (2025) show, political science literature before 2004 was overly optimistic about the democratic prospects of Central and Eastern Europe. The dominant narrative of “successful democratisation“ prevailed, and more cautious, critical accounts were underrepresented in prestigious journals. This optimism had real world effects. As European Union policymakers shared these assumptions. (Dawson, Herman & Ananda, 2025).

Hungary and Poland are the clearest examples of what went wrong since coming to power, Viktor Orban’s government in Hungary has systematically weakened judicial independence, curtailed media freedom, and changed the constitution to consolidate power. Poland under the Law and Justice Party (PiS) followed a similar path. A 2024 master’s thesis from NTNU notes that “ the Hungarian case reveals the weakness of static evaluations of performance and the importance of forward looking scenario planning “ (NTNU student thesis, 2024,, p. 12). Hungary was a stable democracy upon entering the European Union, yet the Union was unable to prevent its democratic backsliding. 

Corruption data confirms this downward trend. The same NTNU study (2024, p. 31) shows that Hungary went from its highest corruption perception index 55 2012 to only 42 and 2022. Poland declined by seven points after  2016 following judicial reform that allowed political appointments. Malta’s call also significantly regressed from 2004 level. Development length to Hungary becoming subject to article 7 proceeding from 2018 (NTNU student thesis, 2024, p. 33). These findings align with Schimmelfennig’s (2024, p. 85) argument that transformative enlargement’s conditionality weakens after accession.

State Capacity and Institutional Development 

Vukov (2024, p. 3063) offers a more nuanced perspective. She argues that the European Union’s success in strengthening state institutions in Central and Eastern Europe was greatest in areas related to economic governance such as competition policy, state aid control, public procurement, and regulatory institutions. (Vukov, 2024, p. 3064).  These reforms reduced corruption and deepened integration with the European Union market, creating domestic coalitions with a stake in accession.

However, Vukov (2024, p. 3065) notes a major difference between the 2004/2007 enlargement and the Western Balkans. In the earlier enlargement, the European Union prioritized economic governance early in the process, reducing governments’ ability to protect politically connected firms. In the economic governance institutions underdeveloped and more vulnerable to state capture. (Vukov, 2024, p. 3065) This suggests that the European Union’s method: when the European Union pushed hard on economic governance, it had a lasting positive impact .

Social Cohesion and Industrial Relations 

The Social dimension of enlargement has also been mixed. As Kahancová, Mrizowicki, and Šćepanovic (2024, p. 3) observe, many people in Central and Eastern Europe hoped for the European Union Model. But twenty years later, the social and wage gap persists, and industrial relations in the region remain fragmented and unstable.  (Kahancová, Marozowicki & Šćepanović, 2024, P. 5). Trade union density has declined, collective productivity growth. In short, the European Union’s Single Market has not brought social convergence to the same degree as economic convergence. (Kahancová, Marozowicki & Šćepanović, 2024).

Part (b) Consequences for the European Union 

Governance Challenges 

The 2004 / 2007 enlargement made the European Union much larger and more diverse. The new member states in the European Union had different levels of socio economic development and different political cultures. This increased diversity made European Union governance more complex. The Decision - making became more congested. The unanimity requirement in the Council of Ministers made it harder to pass legislation. Each new member state in the EU added a potential veto point (Schimmelfenning, 2024, p. 88).

The Istituto Affari Internazionali (2024) confirms that the 2004 enlargement is perceived as one of the causes behind inefficiencies in European Union institutional functioning due to the rise in numbers and heterogeneity of membership. Similarly, the Peace Research Institute Oslo (2024) notes that the enlargement is linked to the insurgence of “Eurofatigue” after the unsuccessful adoption of the European constitution.

The enlargement also changed the institutional balance. The European Commission faced growing competition from intergovernmental elements. The Nice Treaty (2001) attempted to address these issues, but many experts argue the European Union still hasn’t fully adapted. 

The Rule of law Crisis 

Perhaps the most serious political consequence for the European Union has been the rule of law crisis in Hungary and Poland. As Wunsch and Olszewska (2022) argue, the 2004 enlargement sparked renewed interest in the relationship between widening and deepening. Their analysis of parliamentary debates in France, Germany, Hungary, and Poland found that since 2004, there has been a diminished relevance of the external projection of European Union values and instead a stronger introspective emphasis on democratic quality and internal consolidation. (Wunsch and Olszewska, 2022).

This gap  has had practical consequences. Candidate countries, particularly in the Western Balkans, see that European Union membership does not guarantee democratic consolidation. If Hungary can violate European Union values with limited consequences, why should they undertake painful reforms? The European Union’s “normative power” , its ability to shape the behavior of others through attraction and example has been weakened. The European Union had tried to address this new conditionality mechanisms, including the Rule of Law Conditionality Regulation. However, the NTNU study (2024, p. 35) notes that despite Articles 7 and the Commission’s Rule of Law mechanism used against Poland in 2017, the European Union has shown reluctance in taking substantive political measures against Hungary. This reluctance has consequences for future enlargement: problems of rule of law deterioration in newly acceded states must be regarded as internal European Union concerns, raising questions about the European‘s capacity to enlarge to the Western Balkans (NTNU thesis, 2024, p. 36). Schimmelfennig (2024, p. 87) explains that geopolitical enlargement strengthens the membership promise but weakens the threat of non membership to non -compliers.

The Common Agricultural Policy and European Union Budget

The CAP, the Common Agricultural Policy, one of the European Union's largest spending items in the European Union, was a major sticking point. The new member states had large agricultural sectors, and extending (CAP) the Common Agricultural Policy payments to them was expensive. The solution was a phasing in of direct payments over a ten year period. Dwyer, Loughlin, and Short (2006, p . 176) studied how the new member states implemented European Union rural development policy and found that countries made different policy choices from the available measures, balancing multifunctionality oriented and competitiveness oriented approaches. More broadly, the 2004 / 2007 enlargement raised the question of budget reform. The new member states were net beneficiaries, receiving more from the European Union’s Multiannual Financial Framework and contributed to budget disputes .

Geopolitical Lessons for Future Enlargement 

The 2004 / 2007 enlargement also offers lessons for the European Union’s next enlargement. Schimmelfennig (2024, p. 79) argues that the European Union’s recent decision to open accession negotiations with Ukraine and Moldova represents a shift from “transformative enlargement “ focused on domestic reforms to “geopolitical enlargement“ focused on security and territorial consolidation. The war in Ukraine has revived the enlargement momentum. Schimmelfennig (2024, p. 91) argues that the European Union needs to use differentiated integration to overcome the trade offs of geopolitical enlargement. 

Anghel and Jones (2024, p. 3) draw three lessons from the 2004 enlargement: 

1- The pace of accession reflects broader security requirements more than candidate transformation .

2- transformative power is incomplete and requires forward looking analysis. 

3- enlargement changes the experience of membership for all member states. They conclude that enlargement is a strategic imperative, better than the alternatives. (Anghel & Jones, 2024, p. 5).

Kapanasze (2023) adds a regional economic perspective, finding that border regions of CEE countries benefited about 10% less from integration than interior areas, revealing persistent regional disparities. Andor and Watt (2024, p. 378) note that the economic convergence of new member states has been significant, but social convergence has lagged behind, highlighting the need for a more balanced approach to integration. 

Ott (2024) reflects on the 20th anniversary of the Big Bang enlargement, describing the shift from the “return to Europe” narrative to a more critical perspective on democratic backsliding and  rule of law erosion. Hollander (2025) addresses the tension between the European Union’s commitment to its condimental values and diversity that enlargement brings, questioning whether the Union can remain “United in values” while becoming “enlarged in diversity”.

Conclusion: A Mixed Legacy 

The 2004 / 2007 “Big Bang” enlargement had deep and lasting consequences for both the new member states and the European Union. For the new member states, the economic benefits were higher GDP, increased investment, and faster productivity growth. Grassi (2024) calculates a 32% of GDP per capita gain. Hagemejer, Michalek, and Svatko (2021) found that gains increased over time, with five countries achieving at least 30% higher GDP than their counterfactual. But the social and political outcomes were more mixed. Some countries consolidated stable democracies and developed effective institutions. Others experienced democratic backsliding, populism, and the erosion of the rule of law. Labour migration brought both benefits and tensions. The European Union’s economic governance reforms when pushed hard were successful (Vukov, 2024) but the European Union’s influence over domestic politics diminished after accession.

For the European Union enlargement brought geopolitical benefits: stability, security, and a reduced risk of conflict in Central and Eastern Europe, but it also created governance challenges: congestion in decision-making, budget pressures, and internal rule of law crises. The European Union’s credibility as normative power has been undermined by democratic backsliding within its  borders. The lessons of 2004 / 2007 are relevant to the European Union’s next enlargement, which is already underway.

As Vukov (2024) observes, the future enlargement will require the European Union to learn from its past mistakes. If the European Union wants to strengthen state capacity and reduce state capture in candidate countries, it must prioritize economic governance reforms early in the accession process. And if it wants to avoid repeating the rule of law crisis, it must ensure that post accession conditionality is credible and enforceable. Schimmelfennig (2024, p. 94) adds that differentiated integration can help the European Union navigate the trade-offs of geopolitical enlargement, offering fast track membership with limited participation until conditions are met.

References 

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Anghel, V., & Jones, E. (2024). Three lessons from the 2004 "Big Bang" enlargement. Politics and Governance, 12. https://doi.org/10.17645/pag.8358

Dawson, J., Herman, L., & Ananda, A. (2025, April 1). Did political science get Central and Eastern Europe wrong? LSE European Politics and Policy (EUROPP) Blog. https://blogs.lse.ac.uk/europpblog/2025/04/01/did-political-science-get-central-and-eastern-europe-wrong/

Dwyer, J., Loughlin, J., & Short, C. (2006). EU rural development policy in the new member states: Promoting multifunctionality? Journal of Rural Studies, 23(2), 174-185. 

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Thank you