Legal Definitions - landmark decision

A landmark decision is a ruling by a court that significantly alters existing legal principles, establishes new ones, or has a profound and lasting impact on the interpretation of law and society. These decisions often set important precedents that guide future legal cases and policy, fundamentally reshaping a particular area of law.

• Example 1: In Obergefell v. Hodges (2015), the U.S. Supreme Court ruled that the right to marry is guaranteed to same-sex couples by both the Due Process Clause and the Equal Protection Clause of the Fourteenth Amendment to the United States Constitution.

  Explanation: This decision was a landmark because it fundamentally changed marriage law across the entire United States, establishing a nationwide right to same-sex marriage and overturning state bans. It created a new legal standard for equality and significantly impacted the rights of LGBTQ+ individuals.

• Example 2: In Riley v. California (2014), the U.S. Supreme Court unanimously held that police generally need a warrant to search the digital contents of a cell phone seized from an individual who has been arrested.

  Explanation: This ruling was a landmark because it significantly updated Fourth Amendment protections against unreasonable searches to account for modern technology. It recognized that cell phones contain vast amounts of personal data and are not subject to the same "search incident to arrest" exceptions as physical items, thereby creating a new legal standard for digital privacy.

• Example 3: In Massachusetts v. EPA (2007), the U.S. Supreme Court ruled that the Environmental Protection Agency (EPA) has the authority under the Clean Air Act to regulate greenhouse gases as air pollutants.

  Explanation: This decision was a landmark because it was a pivotal moment in environmental law, establishing a legal basis for federal regulation of emissions linked to climate change. It significantly expanded the EPA's mandate and responsibility, setting a precedent for how environmental agencies can address emerging global challenges.