Via Religion Clause, a talk by Supreme Court Justice Stephen Breyer is featured in Washington Jewish Week, focusing on his approach to church-state matters:
"One of the things that is very difficult to me," Breyer said, is determining "what precisely are the values that underlie" the Establishment Clause, which states that Congress shall make no law respecting the establishment of religion. The idea behind the language "comes out of the wars of religion" between Catholics and Protestants in 17th-century Europe, he said, noting that the writers of the Constitution wanted only to ensure that Americans could practice their religion and teach it to their children.
The interpretation of the Establishment Clause has evolved in the 20th century, as the country changed and immigrants introduced dozens of new religions into the United States. "The Founders did engage in a lot of activities that would be forbidden today under … current interpretations of the Establishment Clause," said Breyer, because they lived in a generally homogenous nation. As the nation has changed, the court's view of the Establishment Clause has changed, but Breyer believes it has still stayed true to the original values that the Founders intended.