In the 1970 case of McGee v. United States, the Supreme Court ruled on an appeal by a man convicted for refusing induction into the armed forces during wartime. The appellant argued that his conviction should be overturned because he was not allowed to present evidence at trial about his opposition to war based on religious beliefs. He claimed this violated his First Amendment rights and due process under the Fifth Amendment. However, in a unanimous decision, the Supreme Court upheld McGee's conviction stating that while individuals have a right to express their views against war, they do not have an absolute right to refuse military service when lawfully drafted or enlisted during times of national emergency or conflict.

In the dissenting opinion for McGee v. United States, Justice Harlan argued that the majority's decision to uphold McGee's conviction despite a lack of evidence linking him directly to illegal drugs was incorrect. He believed that this ruling expanded federal power too broadly and threatened individual liberties by allowing convictions based on mere association with known criminals or presence at crime scenes rather than concrete proof of criminal activity. Furthermore, he contended that it undermined the principle of "innocent until proven guilty" by shifting the burden onto defendants to prove their innocence instead of requiring prosecutors to demonstrate guilt beyond reasonable doubt. This could potentially lead to wrongful convictions due simply to an inability or failure in providing such proof, which is fundamentally unfair and contrary to basic principles of justice.