See NCSL's Initiative and Referendum Processes resource for more comprehensive details on citizen initiatives, popular referenda and each state's laws.
Citizen Initiative Overview
In political terminology, the initiative is a process that enables citizens to bypass their state legislature by placing proposed statutes and, in some states, constitutional amendments on the ballot. The first state to adopt the initiative was South Dakota in 1898. Since then, 23 other states have included the initiative process in their constitutions, the most recent being Mississippi in 1992. That makes a total of 24 states with an initiative process.
There are two types of initiatives: direct and indirect. In the direct process, proposals that qualify go directly on the ballot. In the indirect process, the proposal is submitted to the legislature. The legislature can approve the proposed measure, or a substantially similar one, in which case it is unnecessary for the measure to go on the ballot for voters to consider. Procedures vary from state to state, but in general if the legislature has not adopted the proposal, the initiative question goes on the ballot. In some states with the indirect process, the legislature may submit a competing measure that appears on the ballot along with the original proposal.
No two states have exactly the same requirements for qualifying initiatives to be placed on the ballot. Generally, however, the process includes these steps:
(1) preliminary filing of a proposed petition with a designated state official;
(2) review of the petition for conformance with statutory requirements and, in several states, a review of the language of the proposal;
(3) preparation of a ballot title and summary;
(4) circulation of the petition to obtain the required number of signatures of registered voters, usually a percentage of the votes cast for a statewide office in the preceding general election; and
(5) submission of the petitions to the state elections official, who must verify the number of signatures.
If enough valid signatures are obtained, the question goes on the ballot or, in states with the indirect process, is sent to the legislature. Once an initiative is on the ballot, the general requirement for passage is a majority vote, though there are exceptions.
Popular Referendum Overview
The popular referendum is a measure that appears on the ballot as a result of a voter petition drive and is similar to the initiative in that both are triggered by petitions, but there are important differences. The popular referendum allows voters to approve or repeal an act of the Legislature. If the Legislature passes a law that voters do not approve of, they may gather signatures to demand a popular vote on the law. Generally, there is a 90-day period after the law is passed during which the petitioning must take place. Once enough signatures are gathered and verified, the new law appears on the ballot for a popular vote. During the time between passage and the popular vote, the law may not take effect. If voters approve of the law, it takes effect as scheduled. If voters reject the law, it is voided and does not take effect. 24 states have the popular referendum. Most of them are also initiative states.
Legislative Referral (or Referendum) Overview
Legislatures are often required to refer certain measures to the ballot for voter approval. For instance, changes to the state constitution must be approved by voters before they can take effect. Many state legislatures are also required by their state constitutions to refer bond measures and tax changes to the voters. Although this is not always the case, legislative referenda tend to be less controversial than citizen initiatives, are more often approved by voters than citizen initiatives, and often receive higher vote thresholds. Legislative referenda may appear on the ballot in all 50 states.
Another form of referendum or referral, the advisory referendum, is rarely used. In this form of the process, the Legislature, and in some states the governor, may place a question on the ballot to gauge voter opinion. The results of the election on this question are not binding. An example of an advisory referendum is Question 5, which appeared on the Rhode Island ballot in 2002. Placed on the ballot by the governor, Question 5 asked voters if they favored changing the state constitution to make the three branches of government co-equal. Although voters overwhelming voted yes, the question was non-binding and the governor and legislature were not obligated to act upon the measure.