The Supreme Court affirmed that the constitutional right to travel is a personal right guaranteed to all individuals, and it can be asserted against both private interference and governmental action. Durational residency requirements that inhibit the migration of needy persons into a state are unconstitutional, and a classification that penalizes the right to travel violates the Equal Protection Clause unless it is necessary to promote a compelling governmental interest. Discrimination against citizens who have been domiciled in a state for less than a year is subject to a strict standard of review. Discrimination against citizens who have completed their interstate travel is not incidental to the state's welfare scheme, and the right to travel includes the right to be treated equally in a new state of residence. The court has determined that the need for welfare benefits of the respondents and the class they represent is not related to the length of time they have resided in California. The classifications being challenged in this case are based solely on the length of residency in California and the prior residency location of the disfavored class members. California must justify why it is fiscally sound to discriminate against citizens who have been residents for less than a year and why it is acceptable to apply different rules within that class.

The dissenting opinion disagrees with the majority's use of the Privileges or Immunities Clause of the Fourteenth Amendment to strike down a residency requirement. The opinion argues that the statute under consideration does not violate the right to travel since it does not create any obstruction for the respondents' arrival in California. The right to travel and the right to become a citizen are distinct rights under the Fourteenth Amendment's Privileges or Immunities Clause. The Court has established a new framework for defining what residence requirements violate the right to travel. The Court has ruled that a state cannot classify its citizens by the length of their residence in the state, except in certain ill-defined circumstances, without violating the Privileges or Immunities Clause of the Fourteenth Amendment. States can use objective criteria such as durational residence requirements to test a new resident's resolve before granting certain in-state benefits. The Court believes that States should be given deference in allocating limited public welfare funds among potential recipients and that States can require a one-year residence before granting welfare benefits.

The dissenting opinion argues that the majority's interpretation of the Privileges or Immunities Clause in the Fourteenth Amendment was not intended when it was enacted and ratified. The original meaning of the Privileges or Immunities Clause can be traced back to the 1606 Charter of Virginia, which granted all subjects residing in the colonies the same liberties and immunities as if they were born in England. The clause protected fundamental rights and liberties that were enjoyed by citizens of all states, including the right to government protection, life, liberty, property, happiness, and safety, with reasonable restrictions. Other privileges and immunities include the right to travel, habeas corpus, the right to sue in state courts, and to be free from higher taxes than other citizens of the state. The Privileges and Immunities Clause of Article IV only encompasses fundamental rights that belong to all citizens of the United States, not equal access to all public benefits. The Slaughter-House Cases limited the privileges or immunities guaranteed by the Fourteenth Amendment to those belonging to a citizen of the United States as such, but did not specify what those privileges or immunities were.