Supermajority rules in constitutional courts and democratic backsliding: a comparative analysis

Recent scholarship has examined supermajority rules in constitutional courts as mechanisms to supplement deference and address the counter-majoritarian difficulty. Critics have raised several objections, such as that supermajority rules may weaken judicial capacity to resist democratic backsliding. This article compares the role of supermajority rules in democratic backsliding in all identified jurisdictions that had functional supermajority models and experienced significant episodes of democratic backsliding related to supermajority rules, namely Mexico (2024), the Philippines (1973), and Peru (1997). The article concludes that in the three cases examined jurisdictions, two critical features mediated the relationship between supermajority rules and democratic backsliding: prior episodes of highly partisan judicial appointments – typically unilateral or non-plural – and moments of acute constitutional crisis, which encouraged would-be autocrats to allow judicial scrutiny of illiberal reforms based on a strategic calculation of judicial outcomes, and the existence of other possible routes to push forward said policies. These features suggest that the effects attributed to supermajority rules in these three jurisdictions cannot be independently assessed from other institutional conditions, and doing so may lead to overestimating the weight that supermajority rules played in the backsliding episodes, while overlooking other institutional vulnerabilities that may be equally or more consequential.