Why leave one union (UK) to join another (EU)?

Several people have requested the answer to the question “why would Scotland leave one union, the UK, to join another, the EU?”

To make sense, this question relies on the premise that the two unions are similar in how they impact on national sovereignty when they clearly are not.  

A better way to look at the question is to ask what are the differences between the two unions in terms of how they affect the sovereignty of a member-state? We researched the facts and we found the following:  

The Truth about Scotland’s Sovereignty 

Scotland is currently not a sovereign state, as a part of the UK, but an independent Scotland would still be a sovereign country even if it were a member of the EU.

The Facts

  • Scotland is a nation within a union but in terms of statehood the union (UK) is recognised as the sovereign state. Scotland is not a sovereign state and will not be until it achieves independence from the union in a way that is internationally recognised.
  • The power that has been devolved to the Scottish Government is power delegated by the UK government which it can technically remove at any time. So, even though Scotland's Government may for arguments sake have parliamentary control over between 20-30% of the laws that effect Scotland, ‘power devolved is power retained’ and Scotland is not a sovereign state.
  • A basic definition of sovereignty, according to the Online Etymology Dictionary and the Oxford Living Dictionaries, is that it refers to superiority or supremacy usually in terms of the power to make political decisions within a territory.
  • International relations theory, distinguishes between internal and external sovereignty. In short, internal sovereignty is basically a state’s right to self-determination, and external sovereignty refers to the international recognition of a state that enables membership and access to international organisations and resources.1
  • Nowadays, it is widely accepted that state sovereignty is the primary constitutive principle of modern political life.2 This means that sovereignty is a prerequisite for joining international political unions and organisations such as the EU and United Nations (UN).  
  • Participations in political unions and organisations is what what provides a nation with a voice in the international political arena.3
  • Joining the EU is voluntary and so although membership requires the UK to accept and enact on EU laws and regulations that does not mean that the UK parliament’s supremacy over making laws has been reduced. This is because firstly the UK joined voluntarily, had a veto over new treaties and was able to leave when it deemed fit.  
  • By joining the EU, the UK participated actively in the EU’s decision-making processes, which would had otherwise been impossible.
  • The UK, much like Denmark, Poland and Ireland, had the opportunity to negotiate and opt-out from EU legislations such as using the Euro and adopting the Schengen agreement on full freedom of movement of peoples4.
  • The EU is also called a union but it does not require the sovereignty of its members to be transferred to the European Parliment.  Membership does require member states to align the laws that facilitate trade, quality and safety standards etc the elements of a function single market.
  • The UK did not exchange its sovereignty for its EU membership; the ability to hold the 2016 EU referendum through an Act of the Parliament of the United Kingdom (European Union Referendum Act 2015) is the best proof of that. The resulting difficulties of negotiating withdrawal deal and any future difficulties over negotiating trade deals in the 2020 transition period are not a result of a lack of UK sovereignty but rather the lack of the UK’s negotiating power due to the relative sizes of the EU with 27 member states and the UK on its own. 
  • To join the EU a state must be 100% sovereign and thus able both agree to align the required laws and also to leave the EU if it wishes to as the UK has proven.  


Brexit represents a clear cut example that the UK has remained a sovereign country throughout its period of EU membership. This would be the case for an independent Scotland or any other sovereign states joining the EU as equal members. Ironically Brexit demonstrates that Scotland is not at all sovereign, as its democratic wish to Remain in the EU is being ignored as a part of the UK. Regaining sovereignty therefor, either as a member of the EU or otherwise, is one of the strongest arguments for why Scotland should leave the United Kingdom.

On the other hand, the voluntary sharing of sovereignty, in terms of accepting EU legislation, is inevitable in the same way it is inevitable for everyone that decides to be a member of a democratic society to follow its laws and norms as well as to participate actively in their making. This is actually something that enhances rather than reduces sovereignty. 

In an interconnected world with interdependent economies facilitating trade and prosperity through aligning a small percentage of a nations laws with others is what makes a functioning single market possible. This in turn allows sovereign states to gain access to a larger pool of opportunities for development alongside other member-states without the loss of national sovereignty which is required to maintain membership of the UK.


  • James, A. (1984), `Sovereignty: Ground Rule or Gibberish?’ Review of International Studies 10(1), pp. 1-18, p. 2.
  • Walker R.B.J. (1990), ‘Security, Sovereignty, and the Challenge of World Politics,’ Alternatives: Global, Local, Political, Vol. 15, No. 1, pp: 3-27. 
  • Wallace W. (1999), ‘The Sharing of Sovereignty: The European Paradox,’ Political Studies XLVII, pp. 503-521, p. 503.
  • Briggs M. (2015), Europe ‘à la carteʼ: The whats and whys behind UK opt-outs, Euractiv: https://www.euractiv.com/section/uk-europe/linksdossier/europe-a-la-carte-the-whats-and-whys-behind-uk-opt-outs/