In the case of Alabama et al. v. United States et al., 1944, the Supreme Court ruled in favor of the federal government's right to regulate interstate commerce over state laws that might interfere with it. The State of Alabama had imposed a tax on out-of-state vendors selling goods within its borders, which was challenged by several companies as an infringement upon their rights under the Commerce Clause of the U.S Constitution. The court held that while states have some power to impose taxes and regulations on businesses operating within their boundaries, they cannot do so in a way that discriminates against or unduly burdens interstate commerce. This decision reinforced and clarified previous rulings upholding Congress' authority under Article I Section 8 Clause 3 (the "Commerce Clause") to regulate trade among states without interference from individual state laws.

In the dissenting opinion for Alabama et al. v. United States et al., Justice Owen Roberts disagreed with the majority's decision to uphold a federal order that directed railroads in southern states to provide equal accommodations for black passengers, arguing it was an overreach of executive power. He believed this directive violated principles of federalism by infringing on state rights and laws regarding segregation policies at the time. Furthermore, he contended that such orders should be made through legislation passed by Congress rather than directives from administrative agencies like Interstate Commerce Commission (ICC). This case marked one instance where Justice Roberts expressed his concern about expanding powers of federal government and its potential impact on individual liberties and state sovereignty.