In light of ongoing global political changes, there is much discussion in the European Union about the need for “strategic autonomy.” The thinking in EU institutions in Brussels, and among leaders in Paris and some other capitals, is that the global rebalancing of political and economic power away from the North Atlantic requires Europe to develop a more forceful security and defense policy so that it can engage in the geopolitically ascendant Indo-Pacific.

But the Indo-Pacific is far from Europe. Even if France still believes that it has strategic interests there by dint of its overseas territories, the same most certainly does not apply to Europe as a whole. Moreover, even if France aspires to be a Pacific power, it no longer has the requisite strength. Its foreign-policy ambitions must be recognised as mere echoes from a bygone era.

This is not the 18th or 19th century. If a 21st century Pacific power really had aggressive designs on one of France’s far-flung Pacific territories, France would be unable to muster an effective defense. It would be in the same situation as Great Britain vis-a-vis Japan during World War II: totally dependent on the United States.

Because the EU is not, in fact, a global power, it cannot be a stabilising force in global security. Though it faces no shortage of challenges and threats, these emanate primarily from its immediate neighbourhood (mostly the European continent and the Mediterranean) and stem largely from its own internal contradictions. It remains ultimately reliant on the credibility of the US security guarantee for its own defense.

The new debate about “strategic autonomy” follows from the fact that US policies in recent years have called into question the credibility of that guarantee. But if Europeans want to reinforce the principle of mutual defense by increasing their own contribution to transatlantic security (as I believe they should), they ought to look first and foremost to their own neighbourhood.

Until now, the EU has had only one truly effective security-policy tool at its disposal: the promise of accession to the bloc. But since the EU’s great eastward expansion in 2004, it has had to deal with internal crises caused by nationalist governments in Hungary and Poland, both of which have directly challenged the EU by rejecting the supremacy of EU law.

In any case, the enlargement process has effectively ceased, owing to the frictions introduced by previous expansion and older member states’ inability to implement the necessary internal reforms. Yet even though the EU has deprived itself of the means of achieving an independent role in security and foreign-policy matters, it has begun to bang the drum of “strategic autonomy.” This should be recognised as a dangerous contradiction.

It is worth remembering that at the June 2003 Thessaloniki Summit after the war in Kosovo, the EU made a binding commitment that has since underpinned the postwar settlement and maintained the prospects for regional peace. Here is what it said: “The EU reiterates its unequivocal support to the European perspective of the Western Balkan countries. The future of the Balkans is within the European Union. The ongoing enlargement and the signing of the Treaty of Athens in April 2003 inspire and encourage the countries of the Western Balkans to follow the same successful path. Preparation for integration into European structures and ultimate membership into the European Union, through adoption of European standards, is now the big challenge ahead. The Croatian application for EU membership is currently under examination by the Commission. The speed of movement ahead lies in the hands of the countries of the region.”

Ten years later, in 2013, Croatia was admitted to the EU. Reneging on this promise for the region’s other countries, or postponing additional accessions to a later date ad kalendas Graecas (meaning never), would have disastrous consequences. While one can argue over whether Turkey really counts as part of Europe, there is no doubt whatsoever that the Western Balkans do. Nor is there any doubt that instability there poses a danger to the entire continent. The long, violent breakup of Yugoslavia in the 1990s ought to have driven that point home.

On top of this geopolitical risk are the dynamics associated with new great-power rivalries. Russia and China have already shown that they are all too eager to play the Balkan card against the EU. If faith in the EU’s earlier promise to the region were to evaporate, a revival of aggressive nationalism would likely follow, creating the conditions for a return to war.

Viewed from this perspective, the EU simply cannot afford to abandon enlargement, especially not if it is serious about achieving “strategic autonomy.” To be sure, recent internal challenges have shown that modifications to EU governance may be necessary. But breaking the promise of membership is not an option. It is in the Balkans, not the distant Indo-Pacific, that European security and foreign policy must prove itself. And it is in the entire West’s interest that Europe acquit itself well there.

—Project Syndicate