Single-subject rules require that an initiative contain only one issue or subject. The initiative can only address one question.
There are currently 14 states that have a single-subject rule in their I&R law; Alaska, Arizona, California, Colorado, Florida, Missouri, Montana, Nebraska, Nevada, Ohio, Oklahoma,Oregon, Washington and Wyoming.
The purpose of the single-subject rule is to keep the initiative simple and easy for voters to understand. It allows the voter to express clear interest on a single issue. Otherwise, problems may arise where an unfavorable measure is placed in the same initiative as a more favorable measure to garnish more support.
There are disadvantages to the single-subject rule as well. The rule can be so strictly enforced that only the narrowists of subjects can make it on the ballot. It can also lead to the petition being challenged more frequently on the grounds of the single-subject rule, thus hindering the initiative process.