A founding member of Nato, Denmark has long been cautious about the ways in which the European Union has developed into policy areas beyond the sphere of the economy and the common market.
Danes have tended to reject further EU co-operation when asked and secured exemptions in four different policy areas over the years, making this week’s referendum choice to drop their opt-out on defence a watershed moment credited to a shift in public opinion due to the war in Ukraine.
“We are really thrilled,” an EU official said. “This is a historic decision.”
Denmark’s shift is part of a broader transformation in thinking about defence in Europe that has seen neighbouring Finland and Sweden ask to join Nato, and formerly reluctant countries commit to raising military spending.
[ Danes vote overwhelmingly to end EU security and defence opt-outOpens in new window ]
An old Danish concern, common among Nato members, that EU defence could rival or complicate their highly valued transatlantic alliance, seems to have faded as the war has boosted broader western unity. “EU-Nato co-operation is going through a very intensive phase,” an EU official remarked.
As a well-regarded military power, Denmark is seen as a boon to EU defence and is expected to be an important voice in debates about how to develop common security policy.
The topic of security and defence often languished as a contentious issue and a low priority for the EU since it was first conceived in the 1990s in response to the Yugoslav wars, but has been electrified by the Russian invasion.
The strategy has two broad goals.
One is to better co-ordinate between the militaries of EU member states so that their equipment is interoperable and troops are used to working together, so co-operation would be easier in any future conflict.
The other is to send overseas missions with the aim of stabilising the countries that surround the EU, to protect it from the knock-on effects of conflict.
There are currently 11 civilian EU missions, including a project working with Libyan authorities on border checks to manage migration across the Mediterranean. There are six military missions, including a naval anti-piracy project off Somalia and a project to train local security forces in the Central African Republic. There are 4,000 people deployed across the missions in total.
National governments choose which missions to join, and send whatever police, civilian experts, or soldiers they can offer and the project requires, similar to how United Nations missions are staffed.
Denmark already took part in EU civilian missions, and can now join military missions, too (an EU official described organisers as “more than happy” if Denmark chose to do so because “in case of some missions, we have problems with staffing”).
A separate decision by Denmark is needed for it to join Pesco, which is a programme enabling ad-hoc groups of EU member states to come together for joint military training, research or acquisition projects with the help of EU funding.
Ireland already takes part both in EU overseas military and civilian missions and in Pesco, with the government selecting the projects it deems to be in line with the military neutrality policy.
EU debates are focused on developing join defence in two key ways.
One is the plan to form a joint rapid reaction force of 5,000 troops that could be swiftly deployed in a crisis, a suggestion put forward by the recent Strategic Compass review.
Similar joint forces have been established in the past — the EU battle groups, which Ireland has taken part in — but they have never had the political impetus to be deployed.
Now, member states are considering teaming up to buy military equipment jointly, to get the best deal and ensure interoperability — something that takes direct inspiration from the EU’s experience of buying Covid-19 vaccines.