The European Defence Union and Denmark's Defence Opt-out: A Legal Appraisal

Graham Butler*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review


When Denmark failed to ratify the Treaty of Maastricht in 1992, the heads of state and government meeting within the European Council concluded the Edinburgh Decision that established a number of opt-outs for Denmark, so it could subsequently ratify the treaty. One of these opt-outs was in regard to EU defence matters. Nearly three decades on, the Union is now seeing concrete steps being made across the treaties to deliver on a true European Defence Union. Given these developments, the Danish defence opt-out is coming under increased scrutiny. This article analyses the law, policy, and practice of the Danish defence opt-out contained in Article 5 of Protocol (No 22) on the position of Denmark annexed to the EU treaties, in light of the litany of initiatives that now make up the contemporary European Defence Union. Notably, these developments underscore and rationalize the basis of the EU's internal market for deeper European integration. Moreover, with only one Member State possessing such opt-out, it is arguably detrimental to overall EU defence interests. This article contends that the time has come for Denmark to forgo its defence opt-out - a legacy of the past - and participate in the complete range of initiatives contributing to these new endeavours that form the contemporary European Defence Union.
Original languageEnglish
JournalEuropean Foreign Affairs Review
Issue number1
Pages (from-to)117-150
Publication statusPublished - Feb 2020
Externally publishedYes


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