The U.S. Supreme Court case Ansonia Board of Education v. Philbrook in 1986 revolved around the issue of religious accommodation in the workplace, specifically within public schools. The plaintiff, Philbrook, was a teacher who practiced Seventh-day Adventism and requested additional leave for religious observances beyond what was already provided by his employer's policy (three days). When denied by the Ansonia Board of Education, he filed a lawsuit claiming that this refusal violated Title VII of the Civil Rights Act which requires employers to reasonably accommodate employees' religious practices unless it causes undue hardship on business operations. However, the Supreme Court ruled against Philbrook stating that while employers must accommodate employees’ religions to some extent under Title VII, they are not required to give workers their preferred accommodations if other reasonable options exist. In this case since paid leave for certain absences due to personal reasons including religion were available as per contract between teachers union and school board; it constituted reasonable accommodation even though it wasn't exactly what Philbrook asked for.

In the dissenting opinion for Ansonia Board of Education v. Philbrook, Justice Brennan argued that the majority's decision failed to properly interpret Title VII’s reasonable accommodation requirement in relation to religious observances and practices. He contended that an employer must make all possible accommodations unless it can demonstrate undue hardship, not merely one potential accommodation as suggested by the majority ruling. In this case, he believed that allowing unpaid leave for religious holidays was a more reasonable accommodation than forcing employees to use their personal or vacation days. Furthermore, he criticized the court's failure to provide clear guidance on how lower courts should determine what constitutes a "reasonable" accommodation under Title VII law.