Thread by @hhesterm

The discussion about leaving the EU on March 29 because of UK law even though the UK has agreed to an extension of Art. 50 under EU law requires some explanation: on dualism, monism and why what is said is possible, but stupid (thread)

1) The basics: how does international law operate? There are two theories of how international law interacts with national law - monism and dualism. The reality in most countries is more complex. But let‘s go anyways:

Monism. According to monism international law and national law are one and the same. Once a treaty is in force, national courts have to apply them. The administration does, too. As a citizen you can rely on treaties in your dealings with the state.

Dualism. According to dualism international law and national law are two separate orders. Think of Vegas: what happens in Vegas, stays in Vegas. Same in international law: whatever happens there, stays there.

So in a dualist system if you go to a national court or the administration and say “But GATT” they’ll say “GATT? Never heard of such a thing”. For a treaty to have any effect in the national system it’ll have to be transposed into national law.

Who decides who’s monist, who’s dualist? Each state for itself. The reality is that most states have some form of mix (dualist for treaties, monist for customary law) and that they have additional rules (monist, but the norm needs to be self-executing).

But this is twitter. Let’s forget about the details. The UK is dualist for treaties, as are most countries. Against a prevailing myth that’s also true for EU countries. I only know of the Netherlands as a monist system.

2) EU variations. EU law is a bit different: EU Member States don’t get to choose whethere they want to be monist or dualist as to EU law. They are monist and it is the ECJ that decides when a norm has direct application.

Caveat: in the UK, EU law has this effect through the ECA 1972. In practice, this did not really make a difference. In theory, it makes one. And in our storyline, too.

3) So what does this all mean for the national law / international law interplay when it comes to the UK? Because of dualism Parliament can pass rules that differ from the UK’s international obligations and these will be applied in courts / by the administration.

However, the UK will then be in violation of international law and subject to the consequences of that violation under international law.

The current exit date under EU law is layed down in a decision by the European Council, available here assets.publishing.service.gov.uk/government/upl…

The UK has agreed to this withdrawal date and hence to the Art. 50(3) extension here assets.publishing.service.gov.uk/government/upl…

4) So: the UK could just disregard the extension in its national law. Under UK law very likely (small caveat for a court that might think that direct effect comes directly from the EU, not ECA 1972) this means EU law would no longer be in effect domestically.

On the EU level this would, of course, be a severe violation of the UK’s obligation - as the UK would stop abiding by its obligations under EU law and would be a Member State.

Why would that be stupid? The withdrawal date if the WA is not passed and the UK decides that’s it - no long extension wanted - is April 12. Roughly 2 weeks after March 29.

The date has been agreed by the UK government, which also asked for the extension until June. To violate all EU law obligations, just to negate an extension shorter than the one the government actually requested?

That shows to the world (and not just the EU) a supreme level of confusion, doing severe damage to brand UK. And for what? For having your beloved no-deal two weeks earlier.

This is not a serious proposal. This is playing to the base.