When Lore Leads to More: Constitutional Amendments and Interpretation in Mexico 1917-2020

Mexico’s 1917 Constitution has gone through 737 reforms; no other codified constitution has been subjected to such a constant pattern of renewal through amendment. We argue that the study of Mexican patterns offers important theoretical insights for the study of constitutional change by calling into question the generalizability of the thesis—articulated by Donald Lutz and currently endorsed by most specialists in the field—according to which amendment and interpretation are substitute means of constitutional updating. Based on two original data sets containing all constitutional amendments and all Supreme Court precedents on constitutional matters from 1917 to 2020, we find that in Mexico hyper-reformism is correlated to a steep increase in the number and diversity of binding constitutional precedents. Quantitative and qualitative analysis shows that these precedents not only apply the Constitution, but substantively revise it, suggesting that, in Mexico, amendment and interpretation are not alternative but complementary channels of constitutional change. Our account suggests that, in Mexico, hyper-reformism has actually led to innovative constitutional interpretation as a mechanism to cope with its effects. Finally, we discuss the theoretical and comparative insights this case offers for better understanding the nature, causes, and effects of the different modalities of constitutional change.