Justice Brennan agreed that daily prayer and Bible reading in public schools were religious exercises forbidden by the Establishment Clause. He wrote at length to explain that constitutional interpretation should apply the Framers’ broad anti-establishment purposes to modern conditions, rather than seek a conclusive eighteenth-century answer to the precise practice at issue.
He emphasized changes in public education and religious diversity. Modern public schools are publicly financed institutions serving children of many faiths and no faith, and compulsory attendance makes official devotional exercises especially likely to create religious division and pressure on young students.
Brennan reasoned that the exercises could not be justified by their claimed secular benefits. If the objective depends on the religious impact of Bible reading and prayer, both the means and the end are religious; if the objective is truly secular, less sensitive secular alternatives can serve it. The State may not use religious means to attain secular ends when secular means suffice.
He further concluded that rotating Bible versions or calling the exercises nonsectarian could not resolve the constitutional problem. Scripture and prayer remain objectionable to persons of differing faiths, to nonbelievers, and to some believers who regard public devotional use as inappropriate.
Brennan also explained that an opt-out system is constitutionally inadequate. Beyond its irrelevance to establishment, requiring a child to seek an exemption can force a public profession of nonconformity and expose that child to peer pressure, stigma, and exclusion.
Finally, he cautioned that the decision did not demand governmental hostility toward religion. Government may accommodate free exercise in settings such as prisons and the military, where government control otherwise cuts people off from worship opportunities, and schools may teach about religion objectively without sponsoring worship.