Shapiro v. Thompson is a significant Supreme Court case that addressed the constitutionality of state statutes imposing a one-year residency requirement for welfare assistance. In a decision written by Justice William J. Brennan, Jr., the Court found that such residency requirements violated the Equal Protection Clause of the Fourteenth Amendment. The ruling emphasized that the one-year limit not only discriminated against individuals seeking welfare but also unjustly restricted the fundamental right to travel freely across state lines.

The case highlights the tension between state welfare policies and constitutional rights, as the majority opinion underscored the importance of ensuring that all individuals have equitable access to assistance regardless of their residency duration. While the majority viewed the statute as an infringement on both equal protection and the right to travel, dissenting opinions raised concerns about the relevance and scope of these limitations. Chief Justice Earl Warren and Justice Hugo L. Black expressed skepticism about the claimed impact on travel, while Justice John M. Harlan II considered the limitations to be minimal. This case remains a pivotal example of judicial scrutiny regarding state welfare laws and their implications for civil rights.