Thornton resigned and filed a complaint with a Connecticut state agency, asserting that Caldor had illegally discharged him for refusing to work on his Sabbath.

On appeal, however, the Connecticut Supreme Court reversed, holding that because the statute lacked a "clear secular purpose" and its "primary effect" was to confer a religious benefit, it was unconstitutional under the Establishment Clause of the First Amendment.

The Court concluded that "[t]his unyielding weighting in favor of Sabbath observers over all other interests contravenes a fundamental purpose of the Religion Clauses."

However, she concluded that more broadly worded religious accommodation requirements, such as those contained in the Civil Rights Act of 1964, would not be similarly invalid.

In O'Connor's view, a statute requiring "reasonable rather than absolute accommodation" and applying to all religious beliefs and practices "serves the valid secular purpose of securing employment opportunity to all groups in our pluralistic society."