What principle is established by the 1st Amendment?

The First Amendment to the United States Constitution primarily establishes the principle of freedom of religion, among other rights. This amendment prohibits Congress from making laws that would establish a religion or impede the free exercise of religion, thereby ensuring that individuals can practice their faith without government interference. This principle is vital in promoting a diverse society where multiple beliefs can coexist and is foundational to the concept of personal liberty and expression within the United States.

The other principles associated with separation of powers, checks and balances, and due process rights are important elements of American law and governance, but they are not directly addressed in the First Amendment. Separation of powers relates to the division of government responsibilities, checks and balances refers to the mechanisms that prevent any one branch of government from dominating the others, and due process rights are primarily established in the Fifth and Fourteenth Amendments. Therefore, the correct answer focuses on the specific protections and rights guaranteed by the First Amendment, emphasizing religious freedoms as a core tenet of American constitutional law.