COLUMBUS, Ohio — Virtually every poll so far indicates voters will say yes to Issue One on the Ohio ballot, thus revising the state constitution to define marriage as "only a union between one man and one woman."
But in recent weeks the measure has drawn sharp opposition from some surprising quarters. These include the state's top elected Republicans, several prominent education and business leaders, labor groups and the Ohio chapter of AARP, the senior citizens group.
These opponents say a second provision written into the measure is so broad and so vague that it may have what AARP calls "injurious consequences" for tens of thousands of people in the state, both straight and gay, who live together but are not married. Current domestic-partner benefits offered by some state institutions could instantly be subject to legal challenge, they say.
Gov. Bob Taft says passage of Issue One could "make it more difficult for us to retain and attract the young, talented, knowledgeable workers we need to advance Ohio's prosperity in the 21st century."
This sort of heavy-hitting opposition has infuriated the measure's backers, who dismiss it as "chicken-little" arguments.
But the opposition has given a glimmer of hope to gay-rights groups who are bracing for a defeat to the cause of same-sex marriage here and in 9 of 10 other states that have similar measures on the ballot Tuesday.
The exception may be Oregon, where gay-rights groups have undertaken an intensive drive to persuade citizens that they should not tamper with their constitution to weigh in on the issue. A poll released by the Oregonian newspaper Friday found the measure ahead in polls by 4 percentage points -- 50 to 46.
In Ohio, there are plenty of elected officials vigorously in favor of Issue One, including Secretary of State J. Kenneth Blackwell, a Republican and likely gubernatorial candidate in 2006. He says "keeping marriage between one man and one woman is just common sense."
But the governor and both Ohio's Republican senators say the measure would have an unwanted effect. In a recent statement, Taft, who is barred by term limits from running again, called the measure "an ambiguous invitation to litigation that will result in unintended consequences for senior citizens and for any two persons who share living accommodations."
In February, the governor signed a "defense of marriage act" passed by the Legislature which directed Ohio courts not to recognize gay marriages or civil-union ceremonies performed in other states. He said he had no quarrel with the first sentence of the measure on Tuesday's ballot, which describes marriage as a heterosexual union.
It's the second sentence that is at issue. Taft and other critics say it prohibits state and local governments from recognizing a legal basis for relationships of unmarried people that "intends to approximate the design, qualities, significance or effect of marriage."
While most legal experts say it would be unlikely such wording could be used to prohibit private employers from granting benefits to domestic partners, that may not be true for public institutions.
Ohio State University, one of the largest public universities in the nation, grants domestic-partner benefits for its employees. Its president, Karen Holbrook, opposes Issue One.
"Ohio State competes in a global marketplace for the best and brightest," Holbrook said in a statement. Legal challenges to those benefits could harm "our institution's ability to remain competitive with other employers and institutions of higher learning."
Atty. Gen. Jim Petro, a Republican calls the measure "broad, intolerant and unnecessary," and says it could "spark endless lawsuits that cost taxpayers money."
The Ohio Campaign to Protect Marriage, the main group promoting the measure, said the amendment would do nothing to take away the rights of unmarried couples, including benefits that arise from "contracts between private parties."
The group's chief spokesman and strategist, Phil Burress, is president of the Cincinnati-based Citizens for Community Values, which started as a prayer group in the early 1980s and gained national recognition for its lobbying against pornography shops in Cincinnati.
Burress is a bit of an unusual leader for the sanctity-of-marriage cause, having publicly blamed a 25-year addiction to pornography for the failure of his first two marriages. He is married for the third time, saying that he has broken his addiction and wants to help preserve heterosexual marriage as "the most important institution ever created in the history of the world," as he described it to ABC News a week and a half ago.