What are some things Congress cannot do?

While the United States Constitution grants Congress power to do many things, examples of what they are prohibited from doing is the grant or issue of a title of nobility to any person or pass laws restricting religious pursuits, including the development of new religions. While the Constitution primarily states what Congress is charged with doing, there are many things Congress cannot lawfully do.

Other restrictions placed on Congress mainly deal with taxes, individual rights, and equality. For example, Congress cannot:

• Suspend a Writ of Habeus Corpus, except in cases of rebellion or invasion.
• Pass a Bill of Attainder or ex post facto law.
• Impose a tax or duty on articles exported from any state.
• Give preference to the ports of one state over another for import/export.
• Require any transport vessel bound from one state to another to enter, clear, or pay duties.