The EU and NATO have considerable overlap in membership, though not entirely. In the current situation, with enemy artillery and tens of thousands of Russian troops fighting their way across a country on the periphery of the bloc, such division seems increasingly absurd.

Just this week, the European Parliament responded with enthusiasm to Ukraine’s application for membership to the EU. The tiny country of Georgia, directly on Russia’s border, is pursuing membership as well. What sense will it make to admit these countries to the economic and political institutions of Europe without also extending them security guarantees? It would be like the United States admitting two new states while declaring the American military would do nothing to defend them if attacked. That isn’t the behavior of a coherent political entity, and it will have to change.

The simplest way to do it would be for NATO to meld organizationally with the EU, effectively becoming a ready-made Ministry of Continental Defense for the European Union. Countries already in the EU or joining in the future would have to become automatic members of NATO. Over the past week, two EU member nations (Finland and Sweden) have warmed to idea of such a move. If both join, that would leave Austria, Cyprus, Ireland, and Malta as the sole EU members holding out from participating in NATO as well.