Here are a list of precedents for the case.
  Pierce v. Society of Sisters (1925): The Court ruled that the State has a high responsibility for education of its citizens, and thus can impose reasonable regulations for the control and duration of basic education.

Gillette v. U.S. (1971): The Court said that activities of individuals even when religiously based are often subject to regulation by the State in the exercise of their undoubted power to promote the health, safety, and general welfare.

Sherbert v. Verner (1963): The Court held that there are areas of conduct protected by the Free Exercise Clause of the First Amendment and thus beyond the power of the State to control.

Braunfeld v. Brown (1961): The Court ruled that religious freedom-the freedom to believe and to practice strange and it may be foreign creeds has classicially been one of the highest values of our society.

Lemon v. Kurtzman (1971): the Court reemphasized the legitimacy of the State's concern for enforcing minimal eductaional standards.