Amendments are the only things that can become part of the Constitution, unless you want to count judicial activism.
"Judicial activism"; doesn't that qualify as an oxymoron?
Article VI
This Constitution, and the Laws of the United States which shall be made in Pursuance thereof; and all Treaties made, or which shall be made, under the Authority of the United States, shall be the supreme Law of the Land; and the Judges in every State shall be bound thereby, any Thing in the Constitution or Laws of any State to the Contrary notwithstanding.