If Ohio voters approve a proposition known as State Issue No. 1 in November, the state's constitution will be amended to make same-sex marriage illegal, and there will be no civil recognition of any unmarried couples.
Many Christians who believe that homosexuality is a sin are rallying around the proposition, which states, "Only a union between one man and one woman may be a marriage valid in or recognized by this state. This state shall not create or recognize a legal status for unmarried individuals that intends to imitate marriage."
"State Issue 1 is a tremendous mobilizer in the church. We've never seen this level of activity as far as an election has been concerned," said Christopher Long, executive director of Ohio's Christian Coalition.
It was with the help of many Evangelical churches that the proposition got on the ballot in the first place.
Phil Burress, chairman of the Ohio Campaign to Protect Marriage, organized the move to have the issue added to the ballot.
"We are deeply concerned about the courts, not only at the national level, but also here in Ohio. We want to define marriage, we the people. So we put this issue on the ballot to make sure the courts are not the ones to determine marriage," he told ABC News.
Burress said he thinks it's important that marriage be between a man and a woman.
"We have 5,000 years of history of the institution of marriage," he said. "Marriage has always been between one man and one woman, and to define marriage as being between two men and two women is an experiment with children."
State Issue No. 1 has sparked a fierce debate all across the state.
'Not Welcome in Ohio'
Alan Melamed, a Democrat, is the principal spokesman for Ohioans Defending the Constitution, a group opposed to the proposition.
Said Melamed: "The second sentence of this amendment is going to take away rights and benefits from hundreds of thousands of Ohioans. It is going to affect young people that want to buy a house together. It's going to affect people coming to this state looking for domestic partner benefits at our state universities. And when we pass something like this, it's saying that if you don't follow our moral standards, you are not welcome in Ohio."
According to the latest ABC News poll, those in favor of a marriage amendment have a slight edge in Ohio. The opposition is counting on support from the Republican governor, both Republican U.S. senators, and many religious leaders in addition to Evangelical churches.
Burress refutes criticism that suggests the proposition, if passed, could hurt the state's economy.
"I think its going to help our economy," said Burress. "I think marriage is the most important institution ever created in the history of the world. Marriage was created by God. The state and the government have embraced it and understand its importance. To have a marriage defined between one man and one woman is definitely a positive thing for any state."
The fate of State Issue No. 1 will be left up to voter turnout, with faith as one of the state's fault lines. President Bush's embrace of Christianity endears him to Ohio's social conservatives, and the Bush campaign believes that the state's initiative barring gay marriage may catch the tide that will lift and carry the president to victory.
Peter Jennings filed this report for World News Tonight.