The final results show that nearly 67% of voters were in favor of removing the opt-out clause from the EU’s so-called Common Security and Defense Policy.

Denmark will join the European Union’s defense policy after holding a referendum on Wednesday, final results showed, signaling the latest shift among the Nordic countries to deepen defense ties in response to Ukraine’s invasion by Russia.

Denmark is the only EU member that is not part of the bloc’s defense and security policy. The referendum marks the first time that a government has succeeded in abolishing one of the many exemptions won in a 1993 referendum on the Maastricht Treaty.

The final results showed almost 67% of voters backing the removal of the opt-out clause from the EU’s Common Security and Defense Policy (CSDP), in what was the biggest demonstration of support recorded during a referendum on a European issue in Denmark.

About 33% of voters polled opposed it.

The vote to abolish the opt-out is a victory for those in favor of greater cooperation with the EU, while those opposed have argued that the EU defense pact is strained by bureaucracy and that Denmark’s participation in EU military operations will be too costly.

The referendum was the latest example of a European country seeking closer defense ties with allies in response to Russia’s invasion of Ukraine.

It followed historic bids by Sweden and Finland to join NATO – an issue that will be discussed at a summit next month. Denmark and Germany have already promised to increase defense spending sharply.

“We have sent a signal to our NATO allies in Europe. And we sent a clear signal to [Russian President Vladimir] Putin,” Prime Minister Mette Frederiksen said Wednesday night after most of the votes were counted.

“When Putin invades a free and independent country, when Putin threatens peace and stability, we all come together,” Frederiksen said.

Although it is not an outcome that will have significant practical implications for the EU, the outcome will be viewed positively in Brussels and NATO, and is part of a trend towards closer European countries , said Christine Nissen, a researcher at the Danish Institute for International Studies.

“Their willingness to cooperate on security and defense will inspire European countries to play a bigger role so that they take on more responsibility within NATO,” she told Al Jazeera.

The main effect of dropping the opt-out will be that Danish officials will be able to remain in the room when their EU colleagues discuss defense matters, and Danish forces will be able to participate in EU military operations via the PSDC of the block.

A first in 30 years

It is the first time that one of the four Danish derogations from the EU’s Maastricht Treaty, which laid the foundations for political and economic union, has been abandoned by Danish voters.

Denmark is a founding member of NATO, but the alliance’s largest military power, the United States, has signaled that European allies must take greater responsibility for their own security.

“The United States has said that very clearly. I think it makes sense to be part of this cooperation instead of constantly hoping for the United States to come,” said conservative People’s Party leader Soren Pape Poulsen.

For decades, Europe has been a source of contention in Denmark. In 1992, voters rolled back plans to turn European construction into a union by rejecting the Maastricht Treaty amid widespread opposition to a European federal government that could limit the sovereignty of individual nations.

At an EU summit in Edinburgh, Scotland, later that year, EU leaders agreed on text with bespoke provisions allowing the Danes to ratify a revised treaty with four provisions .

They kept the Danes out of a common European citizenship, justice and home affairs, the monetary union which kept the Danes out of the euro and the krona, and defense.