Marriage equality advocates in Ohio took one step closer Tuesday to overturning the state's 2004 constitutional amendment that restricts marriages in the state to only those between one man and one woman.

Ohio Attorney General Mike DeWine (R) approved the petition language for an amendment that would redefine marriage in Ohio as “a union of two consenting adults, regardless of gender," according to the Columbus Dispatch .

The Freedom to Marry Coalition is now tasked with gathering 385,253 valid signatures of registered Ohio voters in order to put its marriage equality amendment on the Ohio ballot -- a goal that Ian James, the group's co-founder, told The Huffington Post he hopes to achieve by November 2013.

Ohio voters overwhelmingly supported an amendment banning gay marriage and health benefits for public employees in domestic partnerships in 2004. The amendment passed by 62 percent, but James said he thinks a lot has changed in the last eight years.

He cited a recent Wall Street Journal/NBC News poll showing that 49 percent of Americans support gay marriage. That's up from 40 percent who approved of the idea when President Barack Obama took office in 2009.

Despite what James calls an "evolution" in voter opinion, he said he's preparing for a ground fight with opposition groups in Ohio by including an explicit exemption for religious institutions in the amendment language.

"This is important because people who are moderately opposed say they are moderately opposed because they don’t want their religious institutions to be forced to perform marriages," James told HuffPost.

James said the exemption is a practical move because "with voters it’s always important to be clear. Ambiguity in ballot issues can be deadly. When it comes to intellectualism vs. emotion in campaigns, emotions always win out."

New York Gov. Andrew Cuomo (D) used the same strategy when he was able to steer his state's marriage equality bill through the Republican-controlled state Senate in 2011. Cuomo's agreement to include the religious exemption helped convince four Republican senators to join almost the entire Senate Democratic caucus to agree to the bill, which had already passed the Democratic-controlled assembly.

Evan Wolfson, who founded Freedom to Marry, a national marriage equality nonprofit that worked to pass New York's law, said he thinks the language is redundant because the U.S. Constitution already protects churches and other religious institutions. His organization is not affiliated with the Freedom to Marry Coalition in Ohio.

"Catholic churches already don't have to marry Protestants, Protestants don't have to marry Jews, Catholic churches don't even have to marry divorced Catholics, but they can all still get civil marriage licenses from the state," Wolfson said.

But Wolfson added that the religious exemption has become an effective tool for passing gay rights legislation, and said he supports its use "if it helps reassure some people that this right wing scare tactic is phony."