The single-subject rule is a part of the Oklahoma Constitution that prohibits individual ballot initiatives and legislation from dealing with more than one main issue. The single-subject rule is found in over 40 state constitutions as a way to prevent “log-rolling”, the legislative practice of combining several distinct matters in one bill.
The Oklahoma Constitution (Article V, Section 57) states, “Every act of the Legislature shall embrace but one subject, which shall be clearly expressed in its title, except general appropriation bills, general revenue bills, and bills adopting a code, digest, or revision of statutes….;”
The Oklahoma Supreme Court has invalidated numerous laws as violations of the single-subject rule, including appropriations bills that provide funding for more than one agency, abortion legislation, tort reform legislation, and a bill that combined funding for State Capitol repairs and an income tax cut. Since 2017, several measures have been introduced proposing to allow voters to amend the Oklahoma Constitution so bills can address a “general” or “comprehensive” subject, but none has been passed.