The Southern African Development Community (SADC) is an intergovernmental organization that promotes regional integration in Southern Africa.Footnote ¹ In 2010, SADC's member states suspended its principal judicial organ, the Tribunal, by depriving it of a quorum.Footnote ² In 2018, the Constitutional Court of South Africa held that the participation of President Jacob Zuma in this maneuver was “unconstitutional, unlawful and irrational” under domestic law (para. 97). The Court's unanimous decision sheds light on the contemporary significance of international adjudication and the role of domestic law in preserving it.

As Chief Justice Mogoeng explained in the majority judgment, after the Tribunal ruled against Zimbabwe in disputes between it and its nationals arising from its program of land expropriation (paras. 10–12), Zimbabwe agreed with South Africa and other SADC member states to block the reappointment or replacement of the Tribunal's judges (para. 15). With the Tribunal unable to function for want of a quorum, South Africa and other SADC member states went on to sign a protocolFootnote ³ in 2014 intended to amend the Tribunal's existing protocolFootnote ⁴ in order to limit its jurisdiction to interstate disputes (para. 16).

The Law Society of South Africa, which represents South African attorneys, and several Zimbabwean farmers brought suit in South Africa contending that, by participating in the suspension of the Tribunal and signing the 2014 protocol, President Zuma violated the South African Constitution. Following an order of constitutional invalidity by the High Court,Footnote ⁵ the applicants sought confirmation before the Constitutional Court.

Before reaching the merits, the majority had to address a preliminary objection as to the application's admissibility. The government argued that the application was premature because the 2014 protocol did not yet bind South Africa (para. 21). The majority acknowledged that Parliament had not ratified the protocol, which itself provides that it will come into force only upon signature and ratification by a “specified number of Member States,” events which had not occurred (para. 22). The majority nevertheless dismissed the objection (para. 42) on five grounds.

First, the majority reasoned that if the Court stayed its hand until ratification, other states might in the interval “sign, ratify and act” on the protocol to the disadvantage of the “citizens of those countries and [South Africa's] own citizens … in those countries” (para. 27). Second, referring to Section 38 of the Constitution, which grants standing in cases in which it is alleged that “a right in the Bill of Rights has been … threatened,” the majority argued that the negotiation and signature of the protocol represented a “threat” to the right of access to justice enjoyed by South African citizens under both the Constitution and the SADC Treaty (Treaty) as well as the “citizens of the rest of the SADC countries” under the Treaty (para. 29). Third, the majority found it appropriate to consider the application because of the signature's immediate impact on South Africa's image abroad (paras. 30–32). Fourth, the majority pointed out that a lengthy period had elapsed without the protocol having been referred to Parliament for its consideration (para. 33).

Fifth, the majority took the view that the signature created a legal obligation for South Africa (paras. 34–41). The majority recalled that Article 18 of the Vienna Convention on the Law of Treaties obliges a state “to refrain from acts which would defeat the object and purpose of a treaty” upon signature, unless it subsequently makes clear its intention “not to become a party.”Footnote ⁶ Although South Africa is not party to the Vienna Convention, the majority held that this provision has effect within the South African legal order because it codifies customary international law (paras. 36–38) and Section 232 of the Constitution provides that “[c]ustomary international law is law in the Republic unless it is inconsistent with the Constitution or an Act of Parliament” (para. 38). According to the majority, there is no conflict between this obligation, which “constrains the State from acting freely” in the interval between the signature of an international agreement and its ratification, and Section 231(2) of the Constitution—according to which an international agreement “binds the Republic only after it has been approved by resolution” in Parliament—because it is a relatively weak obligation (paras. 39–40).

Turning to the merits, the majority stressed that, according to the “principle of legality” enshrined in domestic law, the president “may only exercise power … lawfully conferred on her … in the manner prescribed” and in good faith (paras. 46–49). It pointed out that the Treaty contains “provisions … that regulate its amendment” by the SADC member states (para. 49), among them South Africa, whose representative is the president (para. 43). While these provisions require only two-thirds of the SADC membership to ratify a protocol, they require three quarters of the heads of state or government of the SADC membership to adopt amendments to the Treaty,Footnote ⁷ which includes the Tribunal's existing protocol.Footnote ⁸ In the majority's view, the president and his colleagues went beyond the power of amendment provided for in the Treaty by attempting to revise it by means of a protocol (paras. 49–50), undermining “the entrenchment of a human rights culture, a democratic order and adherence to the rule of law” in the Preamble and Article 4 of the Treaty, to which the Tribunal was set up to “give teeth” (paras. 51–53). Moreover, the attempted modification of the Treaty was not merely ineffective due to the noncompliance with the amendment provisions: because the attempt was inconsistent with the Treaty, it also violated the customary norm of pacta sunt servanda codified in Article 26 of the Vienna Convention (paras. 54–55). The same was true of the suspension of the Tribunal. The majority thus concluded that the president had acted unlawfully (para. 56).

The majority then explained that, under domestic law, decision-making processes must be rational—that is, each process must “be rationally related to the purpose” of the decision (paras. 61–65). In the circumstances of the present case, the question was accordingly whether “the suspension or amendment [was] effected in terms of a process that ensure[d] that our President and his counterparts [did] not lightly veer off the fundamental guarantees and progressive provisions of the Treaty and the spirit of our Constitution” (para. 66). The majority took the view that only the amendment process could have satisfied this test of rationality (paras. 67–71).

Finally, the majority addressed the scope of the power conferred on the president by Section 231(1) of the Constitution, which provides that “[t]he negotiating and signing of all international agreements is the responsibility of the national executive” (para. 29). The starting point of its analysis was that the 2014 protocol “seeks to take away a pre-existing individual right of access to the Tribunal” (para. 72). It observed that, although “it is always open to the Executive to participate in negotiations,” the president cannot “align” South Africa “with decisions that are inimical to our constitutional dream” (para. 76). Consequently, “[t]he President may … not approve anything that undermines our Bill of Rights and international law obligations” (para. 77). The majority reasoned that, in seeking to curtail individual access to the Tribunal inconsistently with the Treaty's amendment provisions, the 2014 protocol falls afoul of this standard (paras. 79–84) and the president's decision to sign it was therefore unconstitutional (para. 85).

On this basis, the majority confirmed the High Court's order and directed the current president, Cyril Ramaphosa, to withdraw the signature (para. 97).

Justice Cameron and Justice Froneman concurred in a minority judgment with which Justice Mhlantla and Acting Justice Petse agreed. The minority sought to draw a sharper distinction than the majority between the international and domestic consequences of President Zuma's conduct. The judges in the minority agreed that the breaches of the Treaty constituted internationally wrongful acts attributable to South Africa (para. 99), but observed that the president could not himself be said to have violated the relevant treaty obligations because they bound the state rather than any individual (para. 100). Instead, the minority concluded that, “[b]y agreeing to amend the Treaty and by thus agreeing to strip away pre-existing rights of access to justice that the Treaty had conferred on South Africans,” the president had violated his constitutional obligation to “respect, protect, promote and fulfil” the Bill of Rights and in particular the right of access to justice (para. 101). Similarly, while the judges in the minority agreed that the president's conduct was “irrational and irregular … under our Constitution,” they held that “this same conduct … did not constitute an international law violation on the part of the President himself” as “[o]nly … the conduct of the South African State” could constitute such a violation (para. 102). This approach, they contended, avoided the need to address “when and how an international treaty becomes domesticated within South Africa” or “engage in the debate on [the] President's individual capacity in the realm of the law of treaties” (paras. 104–05).

* * * *

Although the Tribunal remains in stasis for now, the Constitutional Court's unanimous order suggests that reports of its demise may have been premature.Footnote ⁹ President Ramaphosa has duly withdrawn the signature from the 2014 protocol.Footnote ¹⁰ Moreover, a Tanzanian court has invoked the reasoning of the first-instance judgment confirmed by the Constitutional Court in ordering the Tanzanian government to cooperate in the appointment of new judges to the Tribunal.Footnote ¹¹ But the Tribunal's future remains unclear. For example, shortly before the Constitutional Court's order, the Court of Appeal of Singapore dismissed an appeal against a judgment setting aside an arbitral award that concluded that Lesotho had acted unlawfully by undermining the Tribunal.Footnote ¹²

Its practical consequences aside, the judgment should be studied by those interested in the manner in which domestic law can limit state attempts to modify international legal obligations.Footnote ¹³ Comparison with the first round of litigation between Gina Miller and the government of the United Kingdom over Brexit may be fruitful. Enthusiasm for Brexit has often been linked to concern over the role of the Court of Justice of the European Union (CJEU).Footnote ¹⁴ A consequence of Brexit is that UK residents will eventually lose the right to request that a domestic court make a preliminary reference to the CJEU; they will also be unable to approach the CJEU directly.Footnote ¹⁵ It was partly because withdrawal from the European Union entails the deprivation of these rights that the High Court of England and Wales ruled in 2016 that the prime minister could not trigger this process without legislative approval.Footnote ¹⁶ On appeal, however, the UK Supreme Court focused solely on EU rights “capable of replication in UK law,” such as certain employment protections, as opposed to those concerning participation in EU institutions.Footnote ¹⁷ It is consequently unclear whether the access-to-justice concerns that underlie the Constitutional Court's order would have led to a similar outcome.

By contrast, if the South African Parliament legislates to withdraw from the Rome Statute,Footnote ¹⁸ the majority's reasoning in the present case likely predicts the result of any subsequent litigation. The caseFootnote ¹⁹ concerning South Africa's previous attempt to withdraw has attracted a great deal of commentary.Footnote ²⁰ As that commentary reflects, the High Court upheld the challenge to the attempt on purely procedural grounds,Footnote ²¹ expressly reservingFootnote ²² the question whether withdrawal from the Rome Statute would be substantively irrational or a violation of the government's duty to “respect, protect, promote and fulfil” the Bill of Rights.”Footnote ²³ Given the majority's emphasis in the present case on the rights of the nationals of other SADC member states, along with South Africans, to access justice, it now seems likely that this question would be resolved in the affirmative. This is because South African withdrawal from the Rome Statute would negatively affect the ability of victims of international crimes of all nationalities to access the International Criminal Court if these crimes are committed by a South African or on South African territory.Footnote ²⁴ It is true that the High Court's approach might signal judicial caution about overturning legislation enabling withdrawal.Footnote ²⁵ In the present case, the minority's conscious avoidance of broader questions about the relationship between international law and South African law may reflect something similar. However, the majority embraced Articles 18 and 26 of the Vienna Convention even though doing so limited Parliament's overall constitutional role in international lawmaking. Upholding a substantive challenge to withdrawal from any single treaty—even one as important as the Rome Statute—seems to be a comparatively less assertive exercise of judicial power.

The litigation in the United Kingdom over Brexit and in South Africa over the Rome Statute was as much about the role of international courts as about the constraints that domestic law may place on a state's engagement in international lawmaking in general. The majority's approach in the present case should inform discussion about international courts and their interaction with their domestic counterparts. For example, after the Tribunal's suspension, it was argued that the episode demonstrated the need for a modest conception of the role of international courts in order to avoid alienating the domestic actors on which their effectiveness was said to depend.Footnote ²⁶ Backlash was seen as an almost inevitable consequence of the Tribunal's rulings in favor of a politically unpopular group in Southern Africa—white Zimbabwean farmers—on the basis of an unconventional interpretation of international law.Footnote ²⁷ Yet it appears that the Tribunal did not alienate all of the region's domestic judges, many of whom have since demonstrated their capacity and willingness to support it. Prior to the present case, the Constitutional Court confirmed a lower court's ruling that the Tribunal's judgments are enforceable in South Africa.Footnote ²⁸ Now South African and Tanzanian judges are pressuring executive officials alienated by the Tribunal to reinstate it. This is noteworthy, especially because the Constitutional Court is joining in despite its incentive, as the court at the apex of the South African judicial hierarchy,Footnote ²⁹ to resist the international adjudication of issues over which it would otherwise have the last word.Footnote ³⁰ That said, the majority took care in the present case to “alert” the South African government to the possibility “that disputes relating to issues provided for by both the Treaty and national constitutions are ‘appealable’ or justiciable before the Tribunal even after the highest court of any SADC country has finally disposed of the matter” (paras. 57–60). This hints at potential conflict if the Tribunal emerges from its slumber and challenges the Constitutional Court's “final say.”Footnote ³¹

This storm cloud on the horizon is a further reminder that the place of international courts in today's world is contested.Footnote ³² But consider: the Tribunal has its seat in Windhoek, the capital of Namibia, which the rulers of apartheid South Africa occupied from 1966 until 1990 in repudiation of the “sacred trust” committed to their state after the Great War.Footnote ³³ Doing so defied not only the political organs of the United Nations,Footnote ³⁴ but also the International Court of Justice.Footnote ³⁵ Although many South African judges must have been aware of the illegality of this conduct, having represented the state before the International Court, they proved unwilling to ensure respect for the Court's pronouncements concerning the Mandate for South West Africa.Footnote ³⁶ The stark contrast of the Constitutional Court's defense of the Tribunal is a sign of how far things have come since.