In Shapiro v. United States, the Supreme Court ruled on a case involving wartime price controls and penalties for violations of these controls. The defendant, Shapiro, was convicted under the Emergency Price Control Act of 1942 for selling goods at prices above those set by law during World War II. He appealed his conviction to the Supreme Court arguing that he had been denied due process because he did not have an opportunity to challenge the validity of regulations before being charged with violating them. However, in a unanimous decision delivered by Justice William O. Douglas in 1947, the court upheld Shapiro's conviction stating that Congress has broad powers during times of war and national emergency which includes setting price ceilings as part of its war power authority under Article I Section 8 Clause 18 (the Necessary and Proper Clause) of Constitution; thus it can also provide criminal penalties for violation without prior judicial review.

In the dissenting opinion for Shapiro v. United States, Justice Rutledge argued that the majority's interpretation of the "in furtherance" clause in Section 2(c) of the Sherman Act was too broad and could potentially criminalize innocent behavior. He believed that this interpretation would allow prosecutors to charge individuals with conspiracy even if their actions were not directly related to a larger scheme or plot. Furthermore, he disagreed with the majority's view on evidence sufficiency, arguing that there wasn't enough substantial evidence presented at trial to prove beyond reasonable doubt that Shapiro knowingly participated in a price-fixing conspiracy. Thus, he concluded that Shapiro should have been acquitted due to lack of sufficient proof tying him directly to any illegal activities under antitrust laws.