Labour leader Jeremy Corbyn writes in The Guardian about the proposed Brexit agreement, specifically about the Irish backstop:

There is no precedent I am aware of for a British government signing up to an international treaty it cannot withdraw from without the agreement of other countries.

I'm confused. Isn't it quite usual that international treaties are binding on the signing parties? To take a particularly relevant example, the Good Friday Agreement is an international peace treaty of which the United Kingdom is a party. It is a legal agreement, not just a political intention. Swiss voters recently rejected a referendum to give Swiss law precedence over international law; wouldn't the reverse (the status quo) mean that indeed, when a country signs up to an international agreement, this is legally binding? And doesn't legally binding imply that a party can't legally unilaterally withdraw from it?

Is Corbyn wrong / unaware, or is there indeed something particularly unusual about the binding nature of the backstop in the proposed Brexit agreement — compared to other international treaties of which the United Kingdom is a signatory?

  • 2
    I'm not going to do a proper answer but I'd comment that the purpose of the backstop is to ensure open borders in NI regardless of what else happens. Given that UK gov sometimes does stupid things with NI having a "lock in" to the agreement is the only way to be sure that it will work as intended.
    – Vorsprung
    Dec 7, 2018 at 13:07
  • @Vorsprung Sure, I get that. I'm just surprised that people are commenting such a binding agreement is unprecedented. As I understand it, the Good Friday Agreement is binding on the UK already, so there is not so much that is new.
    – gerrit
    Dec 7, 2018 at 13:11
  • I'm almost certain this has been asked before on the site (in generic form). Can't find it at the moment though.
    – user4012
    Dec 7, 2018 at 13:16
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    Many international treaties have procedures for leaving them. That usually involves a notice period, and any benefits from the treaty would be lost along with the obligations.
    – o.m.
    Dec 7, 2018 at 15:23
  • @o.m. Would you be willing to make that comment an answer?
    – origimbo
    Dec 7, 2018 at 21:17

2 Answers 2


International law gets a bit tricky when it comes to binding vs. enforcable. For some treaties there is no clear-cut answer. Wikipedia summarizes this situation as as:

International law is consent-based governance. This means that a state member may choose to not abide by international law, and even to break its treaty. This is an issue of state sovereignty. International laws are consent-based. Violations of customary international law and peremptory norms (jus cogens) can lead to wars.

The UN's International Court of Justice is theoretically can make decisions binding on UN member states, but the 5 permanent members of the UN Security council, which includes the UK, can each veto any UN enforcement resolution.

Such UN security council vetos happen with a fair degree of regularity, even when the country against whom sanctions are sought are not one of the 5 permanent members, see for example Russia and China veto UN resolution to impose sanctions on Syria, after Syria was accused of violating the chemical weapons treaty.

The statement of Jeremy Corbyn may be interpreted as false by some but practically speaking it seems correct.


Consider Article X of the Nuclear Non-Proliferation Treaty. It allows states to exit with three months notice. Actually doing do so has has political consequences.

Article 18 of the WIPO Convention allows states to leave with six months notice.

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