The divisiveness of the issue was illustrated last week when Washington state's governor signed gay marriage into law and New Jersey's governor vetoed it. In Illinois, Chicago Mayor Rahm Emanuel and several statewide officials back gay marriage, but the topic is replete with potential political repercussions that many lawmakers want to avoid during an election year.
The conventional wisdom in Springfield is that lawmakers will first focus on winning March 20 primary contests as they run in new districts and then attempt to pass a budget and escape the spring session taking as few controversial votes as possible.
"It's going to be a tough year to pass any legislation that's outside of budget and pension issues," said Sen. David Koehler, a Peoria Democrat who championed the civil union legislation. "It's going to more of an election-year agenda in the state Legislature."
Passing gay marriage in Illinois is viewed as difficult in the short term because it would require some lawmakers to undergo philosophical and political shifts. Giving same-sex couples the right to visit a loved one in the hospital, make end-of-life decisions and inherit property through civil unions was considered the middle ground.
Even then, civil unions narrowly passed during a short window between the November 2010 election and the January 2011 swearing-in of the new General Assembly. The bill was aided by votes from lawmakers who weren't returning for another term and no longer feared the wrath of voters.
Taking the extra step of letting gay couples get married increases the intensity of the debate and deepens the opposition's concern.
"To people of faith, in many respects, it's an affront to their faith," said the Rev. Bob Vanden Bosch, who lobbies on behalf of Concerned Christian Americans and the Illinois Family Institute. "I'm not going to say it can't happen, but we'll do everything we can in order to stop it."
Rep. Jil Tracy, R-Quincy, voted against civil unions and opposes same-sex marriage. "The religious basis of marriage is for having children," said Tracy, who is Catholic. "Marriage is for procreation."
In Illinois, at least 3,729 same-sex couples took out civil union licenses during the first six months after the law took effect in June, according to statistics released in December by the advocacy organization Equality Illinois.
The group says it's time to continue the push.
"The only way to reach full equality is marriage," said Randy Hannig, director of public policy for Equality Illinois. "First and foremost, civil unions are separate and unequal."
Rep. Greg Harris, D-Chicago, one sponsor of the gay marriage legislation, said same-sex couples should be treated the same as their neighbors, and civil unions don't provide equitable protection. Marriage licenses are recognized across the country, but many states don't consider civil union licenses valid, he said.
Supporters like Harris are hoping the way the Illinois gay marriage bill is crafted will help win votes. The measure would not force religious organizations to grant marriages to same-sex couples, a move that would make the government benefits of marriage equal for gay and straight couples but still allow the sacrament of marriage to be defined by churches.
Along with Emanuel, supporters include Democratic Lt. Gov. Sheila Simon, Democratic Attorney General Lisa Madigan and Senate President John Cullerton, D-Chicago. Opponents include Republican Treasurer Dan Rutherford, the only GOP senator to vote for civil unions, and House Minority Leader Tom Cross, R-Oswego.
Koehler, the lawmaker who sponsored civil unions in the Senate, would not say how he would vote on gay marriage legislation. The senator, who is an ordained minister with a lesbian daughter, said he would "look at it" if the House passes the bill.
Democratic Gov. Pat Quinn has been coy on the issue.
"I look forward to working with the advocates on this issue to build a majority," Quinn said last week on WBEZ-FM 91.5.
When it was pointed out that sounds like Quinn supports the gay marriage bill, the governor replied: "I think I just said that without me, the last bill, civil unions, wouldn't have passed. You got to work with members from all parts of Illinois, every part of our state, some parts are more liberal than others, and ultimately we'll get to heaven."
The diversity of positions signals another reason why it might take some time before Illinois is ready to approve gay marriage legislation. The pace on gay rights in Illinois is quickening, however: It took several decades to expand civil rights protections for gays and lesbians but only six years after that to pass civil unions.
Even Harris isn't sure gay marriage can pass this spring, but said filing a bill is the necessary first step.
"You can't get to the finish line if you don't start the race," Harris said. "We started the race."