In the case of Aetna Life Insurance Company v. Ward, 1890, the U.S. Supreme Court was tasked with determining whether a Michigan law that imposed taxes on out-of-state insurance companies violated the Commerce Clause of the Constitution. The clause gives Congress exclusive power to regulate interstate commerce and has been interpreted to restrict states from discriminating against or unduly burdening interstate commerce. The court ruled in favor of Aetna Life Insurance Company, finding that Michigan's tax law did indeed violate this provision by imposing an unfair burden on out-of-state insurers compared to their in-state counterparts.

The dissenting opinion in the case of AETNA LIFE INSURANCE COMPANY v. WARD argued that the majority's decision was a departure from established precedent and an overreach of federal power. The dissent took issue with the majority's interpretation of the Constitution’s commerce clause, arguing that it did not give Congress authority to regulate insurance contracts as they were not considered interstate commerce. They contended that such contracts were purely local matters, subject only to state regulation. Furthermore, they disagreed with the notion that life insurance policies could be treated as goods or commodities being transported across state lines for commercial purposes. In their view, this expanded definition would allow virtually any activity to fall under federal jurisdiction if it involved multiple states in some way - a dangerous expansion of federal power at expense of states' rights.