In the case of Hampton, Chairman, U.S. Civil Service Commission v. Mow Sun Wong et al., 1975, the Supreme Court ruled that a federal regulation barring non-citizens from most federal civil service jobs was unconstitutional due to its violation of the Fifth Amendment's guarantee of equal protection under law. The court held that while Congress has broad power over immigration and naturalization policy, this does not extend to allowing administrative agencies like the Civil Service Commission to enact regulations with significant impact on individual rights without explicit Congressional authorization or clear justification in terms of national interest. This decision established an important precedent regarding constitutional protections for non-citizens and limits on executive branch authority.

In the dissenting opinion for Hampton, Chairman, U.S. Civil Service Commission v. Mow Sun Wong et al., Justice Rehnquist argued that the majority's decision to strike down a federal regulation barring non-citizens from most federal civil service jobs was an overreach of judicial power. He contended that it is not within the Court's purview to decide on matters of policy and administration such as this one, which should be left to executive agencies or Congress itself. Furthermore, he disagreed with the majority’s view that due process rights were violated by these regulations; instead asserting they were a legitimate exercise of government authority in managing its own workforce and protecting national interests. In his view, there was no constitutional requirement for individualized hearings before excluding aliens from federal employment because citizenship can reasonably be used as a blanket condition for eligibility.