The fight will first reach the Indiana Statehouse, where the group will press lawmakers to table or defeat the measure.
But if that isn’t successful, the campaign will focus on getting Hoosier voters to beat the prohibition at the ballot box in November.
“All Hoosiers deserve liberty and freedom,” said Megan Robertson, the Republican political operative managing the campaign.
She has worked for the Indiana Republican Party, for the Marion County Republican Party and on two GOP presidential campaigns. She also managed Indianapolis Mayor Greg Ballard’s successful 2011 campaign.
Both sides expect the Indiana battle to draw millions in spending from both in-state and out-of-state interests.
State law already defines marriage as between one man and one woman.
The proposed amendment to the Indiana Constitution to ban gay marriage first passed in 2011, but lawmakers must pass it a second time to send the matter to the public for a vote in November 2014.
The proposed amendment reads, “Only a marriage between one man and one woman shall be valid or recognized as a marriage in Indiana. A legal status identical or substantially similar to that of marriage for unmarried individuals shall not be valid or recognized.”
The second sentence would ban future legislators from enacting civil unions in the future and might affect a host of other laws.
Robertson said public opinion is trending in the opposite direction from that in 2011, and she has spoken to Republican legislators who aren’t comfortable with the wording – especially the unnecessary second line.
Ryan McCann, director of operations and public policy for the Indiana Family Institute, has been lobbying for the constitutional provision for 10 years.
He said he expected organized opposition and still believes, looking at the makeup of the General Assembly and expecting support from legislative leaders, that the measure will pass.
“All it does is allow Indiana citizens to make the choice about what marriage is,” McCann said of the ballot vote. “It’s more proactive than letting a judge do it.”
The Indiana Freedom Coalition includes two of the state’s largest and most prominent employers – Eli Lilly and Company and Cummins.
“A statewide referendum will be expensive and very divisive,” said Rob Smith, director of corporate responsibility for Eli Lilly.
And he noted that etching discrimination into the state’s most important document is hurtful.
Eli Lilly and Cummins have opposed the ban because it limits their ability to attract a quality, diverse workforce.
Other coalition participants include Indiana Equality Action, Freedom to Marry, American Unity Fund and the American Civil Liberties Union of Indiana.
“We are here today to clearly say this amendment permanently threatens liberty for all Hoosiers,” said Chris Paulsen, president of Indiana Equality Action. “I don’t want to be treated as less of a person under a constitution that is supposed to protect everyone.”
Thaddeus Gerardot, founder of Fort Wayne Equality, didn’t attend the event but said his group is working with the coalition to highlight the lives of gay and lesbian people in the community.
“We want to show what this amendment would do to real people – not just talk about it in an ideological sense,” he said.
Public sentiment has shifted dramatically since Republicans started the process, claiming then it was the most critical issue being considered.
In late 2012, a poll conducted by the Bowen Center for Public Affairs at Ball State University found that Indiana residents are evenly divided on whether same-sex couples should be allowed to marry, while a majority supports civil unions.
Fifty-four percent oppose a constitutional amendment banning same-sex marriage in Indiana. But supporters of the amendment question the methodology of that poll.