In Welsh v. United States, the Supreme Court ruled in favor of Elliot Ashton Welsh II who had been convicted for refusing induction into military service during the Vietnam War. The case revolved around whether a conscientious objector to war must have religious beliefs or if moral and ethical convictions were sufficient grounds for objection. Previously, Welsh was denied conscientious objector status because his objections to war were not based on religious training or belief but rather personal moral code and ethics. In a 5-3 decision, the court held that the Selective Service Act's exemption of those who oppose all wars due to their "religious training and belief" should be understood broadly to include deeply-held moral and ethical beliefs as well as traditional religious ones. Therefore, it was unconstitutional under First Amendment free exercise clause principles to deny this status based on lack of traditionally recognized religion-based opposition.

In the dissenting opinion for Welsh v. United States, Justice White argued that the majority's decision to extend conscientious objector status to those who oppose war on moral or ethical grounds rather than religious ones was a misinterpretation of the law. He contended that Congress had clearly intended for this exemption to apply only to those with religious objections when they wrote it into the Universal Military Training and Service Act. Furthermore, he expressed concern about how difficult it would be in practice to distinguish between genuine moral or ethical beliefs and mere personal codes of behavior, potentially opening up an avenue for widespread draft evasion. In his view, such decisions should be left up to Congress rather than being made by courts.