In January 2004, the Philippine Supreme Court nullified provisions of the Philippine Mining Act of 1995 which allowed foreign mining firms to operate in the country. In December of the same year, the Court reversed its January ruling to the dismay of environmentalists, advocates of indigenous peoples' rights, and opponents of economic liberalization. What accounts for the Court reversal? How does one explain the Philippine Supreme Court's overturning of its very own ruling?  The paper explores the factors that contributed to the Supreme Court reversal. The author first conducted an analysis of the text of the Court's two rulings. The aim of the content analysis was to compare and contrast the articulated bases of the Court's January and December rulings. The author then examined the reversal in relation to factors that affect judicial outcomes. According to Paul Wahlbeck, these factors are: (1) judicial preferences, (2) legal constraints, (3) litigation environment, and (4) political environment. According to a Filipino legal luminary, the December reversal resulted from a change in the Court's choice of approach to constitutional interpretation—that is, from a textual and historical approach to a prudential and structural approach. The adoption of a different approach to constitutional interpretation however partly explains the court reversal. The change in the choice of interpretative approach still begs the question: What occasioned the adoption of a new approach to constitutional interpretation and hence the court reversal?