The conversation around letting new countries into the European Union has fundamentally changed. For decades, the talk focused on economics and political reform. Now, the loudest discussion is about defense. Russia’s war in Ukraine made this shift unavoidable. The EU is no longer just a club for peace and prosperity. It must also be a shield.
You can see this new priority in recent actions. In 2024, the bloc started tying financial support for candidate countries to their foreign policy alignment. This was a direct signal. Joining is not just about adopting EU laws. It is about choosing a side in a contested world. The old security blanket, relying on NATO and the United States, feels less certain. As Lithuanian MEP Petras Auštrevičius put it, it is time to look beyond the protection of Uncle Sam.
This creates a complex puzzle. Some countries waiting to join are already NATO members like Albania and Montenegro. Others are not. Serbia maintains military neutrality and deep defense ties with Russia and China. Between 2020 and 2024, over half of Serbia’s arms imports came from China with another twenty percent from Russia, according to the Stockholm International Peace Research Institute. Letting in a country locked into these supply chains poses a real dilemma. It could import strategic vulnerabilities directly into the EU’s core.
But the candidates are not just potential problems. They are also potential assets. Think of the Western Balkans. This region stretches from the Adriatic to the Black Sea. It could become a vital corridor for moving NATO and EU forces. A report from the EU Institute for Security Studies warns that current routes are limited. Bottlenecks could cripple military mobility in a crisis. Investing in corridors through countries like Albania and North Macedonia is not just development aid. It is a direct investment in European security.
The region also holds industrial promise. Analyst Tefta Kelmendi notes the Western Balkans host roughly two hundred defense companies. Bosnia has a dynamic ammunition industry. Montenegro produces military vehicles. Tapping into this capacity could help address the EU’s critical shortages in artillery shells and other hardware. Enlargement can build a stronger European defense industrial base but only if integration happens before membership, not after.
This leads to the toughest question. How does the EU manage the risks that come with these potential rewards? The bloc has one clear model already in place. Cyprus joined in 2004 despite a divided island and no NATO membership. Some see this as a precedent for Ukraine or Moldova. Others see it as a permanent headache. The unresolved conflict remains a source of tension within the EU itself.
New ideas are on the table to avoid repeating past issues. One proposal is reversibility. Benefits of membership, even voting rights, could be suspended if a country backslides on democracy or foreign policy after joining. This creates a lasting incentive for good behavior. It is a tool the EU did not have in earlier enlargements.
The political will for any of this however remains shaky. National elections across Europe are pushing enlargement down the agenda. Many governments are hesitant. The conversation has moved from if to how but the how is fraught with difficulty. As researcher Nicu Popescu frames it, the alternative is grim. A fragmented Europe with parts of it under the influence of hostile powers is a less secure Europe for everyone.
The EU has started to act through new security partnerships. But partnerships are not the same as a shared destiny. The real test is whether Europe can see its neighborhood not as a source of threats to manage but as a perimeter to defend. That requires thinking about enlargement as the construction of a common fortress. The gates must be secure but they also must be open to those willing to stand guard.
- Economic cooperation
- Political reforms
- Military alliances
- Defense strategies
- Foreign policy alignment
- Security infrastructure
| Country | NATO Membership | Defense Ties |
|---|---|---|
| Albania | Yes | N/A |
| Montenegro | Yes | N/A |
| Serbia | No | Russia, China |
| Bosnia | No | Defense industry |
| North Macedonia | Yes | N/A |
| Ukraine | No | N/A |
