The U.S. Supreme Court case Saenz v. Roe, 1998, revolved around a California law that limited the amount of welfare benefits available to newly arrived residents. The law stated that if someone had recently moved to California from another state, their welfare benefits would be capped at the level they would have received in their previous state for up to one year. Brenda Roe and Anna Doe challenged this law on constitutional grounds arguing it violated their right under the Fourteenth Amendment's Privileges or Immunities Clause which guarantees citizens' rights to travel freely between states without being penalized. The Supreme Court ruled in favor of Roe and Doe with a 7-2 decision stating that while states have some power over public assistance programs, they cannot use these programs as tools for discouraging migration by US citizens from other States. The court held that such restrictions not only infringed upon citizen’s fundamental right of free movement but also created an unjust classification based on length of residency.

In the dissenting opinion for Saenz v. Roe, Justice Thomas argued that the majority's interpretation of the Privileges or Immunities Clause was incorrect and overly broad. He contended that this clause only protects rights specifically enumerated in the Constitution, not a general right to travel or change residency. Furthermore, he disagreed with their application of equal protection principles to strike down California's welfare law limiting benefits for new residents. According to him, states should have wide latitude in setting their own social policies without interference from federal courts unless there is clear evidence of unconstitutional discrimination. He believed California had legitimate reasons for its policy such as preventing welfare tourism and preserving limited resources for long-term residents.