International law and pacta sunt servanda

This post has been contributed by Professor Wade Mansell, Module Convenor for Public International law.

It may seem strange that a Public International law blog concerning a contemporary matter of importance should be concerned with possibly the most fundamental principle upon which international law depends – that of pacta sunt servanda, with which I know I can assume familiarity. It does of course, crudely interpreted, mean that international law requires that promises must be kept. It underlies treaty law obviously but also extends beyond treaty law to ensure unilateral statements made on behalf of states also are binding upon the state on whose behalf they are made. (Nuclear Tests Case, Australia v. France 1974 ICJ Reports p.253)

Nevertheless, as your Mansell and Openshaw text observes at p.324, while because it is a legal principle, it is generally accepted uncritically, this does not mean that a state will invariably comply with the principle. On rare occasions, having carried out something of a cost/benefit analysis, a state might conclude that the downside of breaching a given undertaking is outweighed by the advantages. The downside, ‘even if there is no direct sanction, will rarely be cost-free, even if it involves nothing more than enduring a certain amount of disapprobation from other states, or a hesitancy upon their part to enter into future international legal relations’. Furthermore it is clear that the more powerful a state, the less it might seem to have to lose by breaking such a legal rule. Arguably this could be exemplified (as does John Bolton) by the USA’s refusal to pay the United Nation’s assessed dues as promised. It could also be exemplified by the refusal of China to comply with a ruling in an arbitration case between the Philippines and the PRC heard by a five-judge panel formed under the ‘Settlement of Disputes’ process provided for in Part XV of the United Nations Convention on the Law of the Sea, and concerning a range of issues relevant to the continuing sovereignty disputes in the South China Sea. (China is party to this Convention, but refused to take part in the ‘arbitration’ arguing as it did that the case was a legal nullity, because of Beijing’s ‘undisputed sovereignty’ of the features in the South China Sea.)

It is nonetheless quite exceptional for a state to announce, as did Brandon Lewis, then Northern Ireland Secretary in the UK Government, when in Parliament on 7 September, 2021, that a provision in the Internal Market Bill then being debated, ‘does break international law in a very specific and limited way’.  While subsequent events make the implementation of this provision unlikely, the issue remains important.  Brandon Lewis suggested that for a state to renege on its promises was not unusual where circumstances had changed (although he provided no examples) but it has to be observed that nothing had changed since the signing by the UK and the EU of the ‘The Withdrawal Agreement’ which is the legally binding part of the divorce deal that the Johnson government settled with the EU, in the autumn of 2019. Setting out the terms of the UK’s departure, it has the force of an international treaty.  (This post takes no view on the UK’s decision to leave the EU).

One major issue with which it dealt, was the question as to where the border between the EU  and the now newly separate independent state, should be established. While those unfamiliar with Irish history might have concluded that it obviously should have been where the EU ended and the UK began this would have meant a real (or ‘hard’) border separating Northern Ireland (a part of the UK) from the Irish Republic.  To have done this would have been to breach the so-called Good Friday Agreement. This is an agreement reached after two years negotiation and with considerable help from the USA, which effectively secured peace by removing the physical border between the two parts of Ireland

Arrangements concerning the politically sensitive border between the UK territory of Northern Ireland and the Republic of Ireland, an EU member, were at the heart of the British parliamentary deadlock that led to Brexit being delayed in 2019, and contributed to Theresa May’s downfall.

The Johnson government sought to avoid the issue by accepting the Withdrawal Agreement which included the ‘Northern Ireland Protocol’ and promising to implement its provisions.  Securing the Withdrawal Agreement was an important factor in the subsequent election with the Tory promise to ‘Get Brexit done’ being persuasive.  The UK Government now argues that notwithstanding agreeing to the Northern Ireland Protocol which effectively accepted a border provision between Great Britain and Northern Ireland, with Northern Ireland remaining within the EU subject to its provisions, as is the Republic of Ireland, with consequential regulatory obstacles for trade between Great Britain and Northern Ireland (as there would be between any third party state and the EU). 

Notwithstanding having signed the Agreement after prolonged negotiations, the UK Government wishes to argue that the agreed Protocol has had ‘unexpected consequences’ which, if they cannot be resolved through renegotiation will ‘force’ the Government to trigger Article 16 (for details of this see the BBC article Brexit: What is Article 16 of the Northern Ireland protocol?

In essence, the effect of this ‘triggering’ would have the effect of meaning that the Government, having understood the consequences of giving its word to secure the Agreement, is now prepared to break what it promised unless the EU agrees to renegotiate agreed provisions.  Even Therese May, Johnson’s predecessor prime minister, stated when Brandon Lewis first proposed breaking international law, ‘The government is now changing the operation of that agreement. Given that, how can the government reassure future international partners that the UK can be trusted to abide by the legal obligations of the agreements it signs?’  Her question remains pertinent.

Leave a Reply