Environmental Constitutionalism and Indigenous Land Rights in the Brazilian Amazon: Judicial Enforcement Challenges Under Article 231 of the 1988 Federal Constitution

Article 231 of Brazil's 1988 Federal Constitution provides one of the most robust frameworks of indigenous land rights protection in comparative constitutional law, recognising indigenous peoples' original rights over their traditionally occupied territories and mandating the Union to demarcate and protect these lands. Similarly, Article 225 enshrines a fundamental right to an ecologically balanced environment enforceable against both state and private actors. Yet the enforcement of these provisions in the context of the Brazilian Amazon has been characterised by persistent institutional failures, judicial inconsistency, and escalating legislative encroachment. This article undertakes a critical doctrinal analysis of Supremo Tribunal Federal (STF) jurisprudence on indigenous land demarcation between 2015 and 2024, with particular focus on the contested marco temporal (time frame) doctrine and its implications for indigenous land rights. We analyse the landmark STF judgment in Recurso Extraordinário 1.017.365/SC (2023), which repudiated the marco temporal thesis as unconstitutional, and the subsequent enactment of Lei No. 14.701/2023 by the National Congress, which purported to legislate the same doctrine into positive law. Drawing on comparative indigenous rights jurisprudence from the Inter-American Court of Human Rights and the UN Declaration on the Rights of Indigenous Peoples, the article proposes a rights-based enforcement framework grounded in the principle of constitutional supremacy and the prohibition on retrogression in fundamental rights.

Keywords: Indigenous Land Rights; Amazon; Brazilian Constitution; Marco Temporal; Environmental Constitutionalism; STF; UNDRIP; Deforestation; Article 231; Demarcation