- January 10, 1356 – The first 23 chapters of the Golden Bull of 1356 are created, fixing important aspects of the constitutional structure of the Holy Roman Empire.
- January 2, 1975 – The Federal Rules of Evidence are approved by the United States Congress.
- January 22, 1973 – Roe v. Wade, 410 U.S. 113 (1973), decided, finding a constitutional right to abortion in the United States.
