Final answer:
The Supreme Court ruled in Pierce v. Society of Sisters that an Oregon law mandating public school education violated the 14th Amendment, was unconstitutional, and did not focus on the First or Second Amendments.
Step-by-step explanation:
In the case of Pierce v. Society of Sisters, the Supreme Court decided that an Oregon law mandating public school education violated the 14th Amendment rights of parents to control their children's education and the ability of private schools to conduct business.
The law compelled parents to send their children to public schools, which the Court found to be an unconstitutional overreach of government power. Thus, the final answer to whether the Supreme Court's decision in Pierce v. Society of Sisters was that an Oregon public school law violated the First Amendment was that it was unconstitutional. This case was not primarily about the First or Second Amendment, as it centered on the Due Process Clause of the 14th Amendment.