A more thorough explanation:

Definition: Graham v. Richardson is a landmark case in which the Supreme Court of the United States held that state attempts to deny welfare benefits to legally resident aliens violate the Equal Protection Clause of the 14th Amendment to the U.S. Constitution and the exclusive powers of the federal government in immigration matters. The case involved Arizona and Pennsylvania, which sought to require either U.S. citizenship or residence in the country for a certain number of years, violating equal protection of the laws and the exclusive power of Congress. The Supreme Court held that legal aliens are a suspect class to whom discrimination is subject to heightened judicial scrutiny.

Example: Arizona passed a law restricting social welfare benefits to U.S. citizens or residents of the country for at least 15 years, while Pennsylvania granted social welfare benefits to U.S. citizens but denied them to aliens regardless of duration of residency. These laws were found to be unconstitutional by the Supreme Court in Graham v. Richardson.

Explanation: The examples illustrate how the states of Arizona and Pennsylvania attempted to discriminate against legal aliens by denying them social welfare benefits. The Supreme Court held that such discrimination violated the Equal Protection Clause of the 14th Amendment and the exclusive powers of the federal government in immigration matters. The Court also held that legal aliens are a suspect class to whom discrimination is subject to heightened judicial scrutiny.