The Bill of Rights.
During the debates on the adoption of the Constitution, its opponents repeatedly charged that the Constitution, as drafted, would open the way to tyranny by the federal government. They demanded a "bill of rights" that would spell out the immunities of individual citizens. Several state conventions in their formal ratification of the Constitution asked for such amendments; others ratified the Constitution with the understanding that the amendments would be offered.
The first of ten amendments allow citizens to participate in the political process. One such right was freedom of religion which grants citizens the right to practice any religion they choose, in any way they choose (so long as they don't cause anyone serious harm). Although religious practices vary, laws remain the same; no practicing of polygamy, no use of illegal drugs, and someone who believes that war is, according to their religion, immoral, can still be drafted into the army. Another right is the freedom of speech; expressing oneself verbally without slander, libel, being obscene, or practicing illegal use of symbolic speech. The last right in the first amendment allows freedom of the press which does not allow censorship, or rules telling the newspaper in advance what it can, or cannot publish. In effect, if someone writes an article, and something in it is slanderous or anything of the sort the journalist is due his or her own consequences.
The second amendment gives people the right to bear arms, as long as the person has an adequate license. The third amendment sees that troops are not allowed to "welcome" themselves into civilian homes during peacetime. And even during war they need a court order.
The fourth amendment through the eighth amendment protect against arbitrary police and court action. The fourth amendment forbids unreasonable searches or seizures.