Between a Treaty and Not: A Case Study of the Legal Value of Diplomatic Assurances in Expulsion Cases

Abstract

Diplomatic assurances issued by states declaring that they will not mistreat individuals returned to them occupy a strange middle ground between being legal and non-legal obligations. In turn, unless we want to largely avoid the issue of legal value, the question of their value forces us to re-evaluate our understanding of the law of treaties. However, international law, and law in general, requires a binary approach to obligation; either there is a legal obligation or not. All communications must be placed in one of those categories, even if the fit is not precise. Through this study we will find that some of the obligations in certain assurances can be understood as legal obligations and some not. We will conclude that we can state a methodology for determining which obligations are legal under the law of treaties (not necessary the most clear methodology, but at least we can find one). In turn, perhaps this examination of this one type of international communication can shed light on the larger phenomenon of soft law instruments and similar instruments whose legal value is unclear.

The paper begins in Section II with some background of the legal environment of diplomatic assurances and their use in cases of expulsion. Section III discusses the legal nature of diplomatic assurances, proceeding to discuss various possibilities for legal value in Sub-section A, regarding diplomatic assurances as treaties; Sub-section B, regarding diplomatic assurances as binding unilateral statements; and Sub-section C, regarding diplomatic assurances as subsequent practice that would inform treaty interpretation. This paper will not examine the legal value of diplomatic assurances under customary international law other than the way in which customary international law might further refine the definition of treaty.

By far the longest examination will be in Sub-section A on whether diplomatic assurances could be considered treaties. The reason for this choice is that whether diplomatic assurances, which purport to be non-legally binding, could qualify as treaties is the most controversial of the various examinations with strong arguments on either side, arguments that are both, in the end, unsatisfactory. This sub-section thus forms the most difficult part of the paper and is hopefully the most interesting for international law in general.

Keywords: assurances, treaty, international, soft, dispute, formal, binding, unilateral, subsquent

JEL Classification: K33, K39, K30, K40, K41, K42, K00