Denmark's decision to join the European Union's defense and security cooperation framework marks another step in deepening Nordic countries' military integration with the rest of Europe in response to Russia's invasion of Ukraine. Aside from potentially giving a political boost to the ruling party, the move will give Copenhagen more influence over, and access to, European defense cooperation, while allowing the European Union to complete its security architecture. On June 1, two-thirds of Danish voters in a referendum supported joining the European Union's Common Security and Defence Policy (CSDP), ending their country's 30-year-long opt-out from the bloc's defense cooperation mechanism. This decision ends one of many exemptions that Copenhagen obtained when it signed the Maastricht Treaty that created the EU in 1993. The final results showed almost 67% of voters were in favor of greater EU cooperation on defense and security, while around 33% of voters were opposed.