IN 1967, THE HEAVYWEIGHT BOXING CHAMPION OF THE world, Muhammad Ali, was stripped of his title and sentenced to five years in jail for refusing to report for induction into the army. The country was then at war in Vietnam. The nation had a draft. But when called, Ali refused to take what the Supreme Court described as “the traditional step forward,” and he was prosecuted as a result. His defense was straightforward: the draft law then in force provided exemptions for those who, because of sincere religious belief, were conscientiously opposed to war in any form. As a newly converted member of the Nation of Islam, Ali claimed entitlement to “conscientious objector” status.

Although the appeals process took five years, in Clay, also known as Ali v. United States (1971), the Supreme Court overturned Ali’s conviction. The Court based its decision entirely on the draft laws then in effect. It held that draft officials had erred in their consideration of whether Ali was entitled to a draft exemption as a religiously motivated conscientious objector. Nevertheless, difficult, controversial, and tangled constitutional issues were not far in the background. To grasp why is to understand what is perhaps the central issue in constitutional doctrines involving freedom of religion.