U.S. Supreme Court rejects challenge to New Jersey affordable housing law

The U.S. Supreme Court has refused to block New Jersey’s new affordable housing law, allowing the state’s updated framework for requiring municipalities to plan for affordable homes to continue moving forward.

Justice SamuelAlito Jr. denied an emergency application seeking to delay implementation of the 2024 law, known as A4/S50, ending the latest attempt by a group of municipalities to stop the policy through federal courts.

The decision follows a series of losses for the towns challenging the law. In January, the U.S. Court of Appeals for the Third Circuit rejected a similar emergency appeal after U.S. District Judge Zahid N. Quraishi dismissed the municipalities’ lawsuit and declined to pause the law. State courts had already rejected comparable claims multiple times, including a September ruling by Mercer County Superior Court Judge Robert Lougy dismissing the case with prejudice.

Courts at every level of the state and federal judiciary have now declined to intervene, marking the eighth unsuccessful legal challenge to the law’s implementation.

The lawsuit was filed by roughly three dozen municipalities led by the Bergen County borough of Montvale. Many of the participating towns are affluent suburban communities that argued the legislation improperly reshaped New Jersey’s affordable housing system and imposed unlawful requirements on local governments.

New Jersey’s affordable housing obligations stem from the state Supreme Court’s Mount Laurel doctrine, which requires every municipality to provide opportunities for its “fair share” of affordable housing. Those obligations are recalculated every decade based on regional housing need, job growth, and demographic trends.

The current cycle, known as the Fourth Round, began in 2025. Lawmakers passed A4/S50 to standardize how obligations are calculated and to reduce years of litigation that historically slowed housing construction.

Under the law, municipalities retain significant discretion over how they meet their obligations. Options include zoning for mixed-income developments, building entirely affordable projects, creating supportive housing, or redeveloping vacant commercial properties such as aging office parks or shopping centers. Towns that refuse to comply risk losing control of the planning process through court intervention.

After a Dec. 31 deadline to resolve disputes through mediation, about 380 municipalities had submitted housing plans considered compliant with the new framework, according to data released by Fair Share Housing Center, a nonprofit involved in monitoring enforcement of affordable housing requirements.

The municipalities challenging the law argued, among other claims, that the framework improperly treated suburban and urban communities. Courts rejected those arguments, noting that cities often face separate obligations tied to rehabilitating existing affordable housing stock, which can involve thousands of units.

While New Jersey’s housing requirements remain governed by state law, the federal lawsuit sought to frame the dispute as a constitutional challenge. Judges repeatedly found the claims insufficient to justify blocking implementation.

The law’s supporters argue it brings predictability to a system long dominated by lawsuits, while opponents have warned it could strain local infrastructure and limit municipal control over development decisions.