The case of South Dakota v. Dole, Secretary of Transportation involves a law that directs the Secretary of Transportation to withhold a percentage of federal highway funds from states that allow the purchase or public possession of alcoholic beverages by persons under the age of 21. The State of South Dakota sued, claiming that the law violated constitutional limitations on congressional spending power and the Twenty-first Amendment. The District Court and Court of Appeals both rejected the State's claims. The parties in the case are debating the proper scope of the Twenty-first Amendment, with South Dakota arguing that setting minimum drinking ages is a core power reserved to the states under the Amendment, while the Secretary of Transportation argues that the Amendment does not confer on states the power to permit sales that Congress seeks to prohibit. The Secretary contends that the Amendment would not prevent Congress from enacting a national minimum drinking age more restrictive than state laws, and therefore the indirect inducement in the law is compatible with the Amendment. The case raises questions about the interpretation of the Twenty-first Amendment, which has not been precisely defined. Congress has the power to collect taxes and attach conditions to the receipt of federal funds in order to further broad policy objectives. The Supreme Court has determined that the power of Congress to authorize expenditure of public funds is not limited by the direct grants of legislative power found in the Constitution. However, the spending power is subject to limitations, including the requirement that it be in pursuit of the general welfare and that Congress must unambiguously condition the receipt of federal funds. Courts should defer to Congress's judgment in determining whether a particular expenditure serves general public purposes.

South Dakota's challenge to §158 fails because the Twenty-first Amendment does not prevent Congress from using the spending power to regulate drinking ages. Federal grants can be conditioned upon state cooperation with federal plans for the general welfare. The grant of federal funds conditioned on raising the drinking age to 21 is constitutional and not coercive. The lower court did not err in its interpretation. Justices Brennan and O'Connor dissent from the majority opinion. Justice Brennan argues that the regulation of the minimum age of liquor purchasers is within the power of the states under the Twenty-first Amendment, and Congress cannot infringe on this right. Justice O'Connor argues that the National Minimum Drinking Age Amendment is outside Congress' power to regulate commerce and falls within the scope of the Twenty-first Amendment. The author disagrees with the Court's decision on the application of a principle related to the spending power, but their disagreement is narrow and related to the application of a principle rather than the principle itself.

The author disagrees with the Court's conclusion that Congress can condition grants under the spending power if they are reasonably related to the purpose of the relevant federal program. They argue that the minimum legal drinking age of 21 is not closely linked enough to interstate highway construction to justify conditioning funds allocated for that purpose. The Court's reasoning is flawed because the condition is over-inclusive and under-inclusive, and statistics show that drivers over the age of 21 are responsible for the majority of highway fatalities involving alcohol. Congress can require that highways be safe, but it cannot condition the use of highway funds on the State changing regulations in other areas of social and economic life that have only an attenuated or tangential relationship to highway use or safety. The Court must draw a clear line between permissible and impermissible conditions on federal grants.

Congress can only attach conditions to grants that are related to the expenditure of federal funds. The condition that a state must raise its drinking age to 21 in order to receive federal highway funds is not related to the expenditure of those funds and therefore not justified by the spending power. The regulation of the age of liquor purchasers falls within the scope of powers reserved to the states by the Twenty-first Amendment, and the federal government cannot use its Commerce Clause powers to interfere with the states' exercise of that power. The statute in question cannot be justified as an exercise of any delegated power and is not authorized by the Constitution. The Court's decision is in error.