The correct answer is the United States Constitution.
The US constitution consists of republicanism and individual rights. For example, the US Constitution establishes a republic form of government. This means that citizens have the power to vote for officials to fill positions in the government and to make laws on their behalf.
The Constitution also embeds individual rights in the Bill of Rights. The Bill of Rights consists of the first 10 amendments of the US Constitution. These rights are protected and can never be taken away by the government. This includes the freedom of speech, freedom of religion, right to petition, right to bear arms, etc.