Gay marriage proponents want voters to change the Arizona constitution to define marriage as between two persons rather than a man and a woman.
Equal Marriage Arizona submitted paperwork to launch their campaign Monday with the Arizona Secretary of State's office.
The petition drive comes as the U.S. Supreme Court is expected to release its ruling this month on gay marriage.
Equal Marriage Arizona hopes to collect roughly 400,000 signatures to get its initiative on the ballot in 2014.
If the effort is successful, it would essentially overturn a state constitutional ban on same-sex marriages approved by voters in 2008.
The proposed constitutional amendment says religious organizations won't be required to officiate a gay marriage under the First Amendment, which protects religious freedom.
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