Thread by @alexebarker

The Walloon Solution, codicils, the Danish-Dutch fix -- what on earth does all this have to do with Brexit?

Here's my (probably futile) attempt to explain

The challenge: Theresa May needs a legally binding reassurance on the Northern Ireland backstop that does not actually change Britain's exit treaty.

The Danes faced this problem in 1992 when they voted down the Maastricht treaty.

With (a little) help from the Brits and some nifty footwork from @piris_jc a creative solution was found.

(@OleRyborg says it was first written on a copy of the FT during a Brazil-Norway flight)

It created a legal instrument -- a decision of EU leaders -- that was agreed within the European Council, but was not an EU act.

Why so convoluted? It provided a fuss-free way to make a binding promise on how to interpret a treaty, without changing the treaty or EU law.

For the geeks -- take a look at how this Council legal service opinion explains the legal shimmy.

Wonderful stuff.

The Danish solution spawned many future fudges.

The Irish used it over the Lisbon treaty, the Dutch over the EU-Ukraine deal and David Cameron in his pre-referendum re-negotiation of UK membership terms.

ft.com/content/6563aa…

Naturally enough May and her team raised Danish-Dutch option with the Hague when looking for way to provide binding reassurances on the Nothern Ireland backstop

But there was a legal hitch in the case of Brexit -- it may require national ratification.

So Britain eyed up an alternative: The Walloon Solution.

This rescued the EU from a tight spot on the EU-Canada trade agreement (Ceta) in 2016.

It is a "Joint Interpretative Instrument" that won round the naysayers in a veto-wielding region of Belgium that *loves* to be involved in complex trade deals.

(Warning to Brits: this may not be the last you hear of Wallonia)

ft.com/content/a614ae…

It's legal force comes from Article 31(2) of the Vienna Convention on the law of treaties.

NOTHING is changed in the original treaty itself. But the instrument provides "context" to help interpret its provisions

For now the EU is telling Mrs May it is not possible and putting up (light) resistance.

The more significant point: the more legally binding the document is, the more it has to stick to the content of the treaty.

Because ultimately the EU think its interpretation is clear.

How does this differ from the Dutch-Danish solution?

The main difference is that the Wallonia deal involved Canada as a joint signatory

It's all explained here by the Council legal service.

Is this the codicil that some UK ministers have mentioned?

If it is meant to modify or revoke parts of the treaty, definitely not.

The full Walloon thing reads like a summary of the Ceta text because in essence it is.

data.consilium.europa.eu/doc/document/S…

There is a option to go further, which is provided for in the Vienna Convention.

This is known as a Reservation, which a state can add to a treaty it is ratifying.

That's covered by articles 19-23 of the treaty

It would carry much more legal force, and so would be much, much harder to negotiate or attach.

The Council Legal service here explains that in terms of ratification and approval, it's basically the same as reopening the treaty.

So in summary: what do the Danish or Walloon fixes achieve?

The substance of the original treaty stays the same.

But if doubts arise on what the substance may imply, the texts can exclude certain interpretations, and might help in court.

The Council Legal Service again:

Basically Mrs May is putting her faith in the Walloon solution, at least for now.

ft.com/content/4607b4…