CHICAGO (AP) — Emboldened by recent victories at the polls and what they see as rapidly shifting attitudes in favor of gay rights, supporters say Illinois is ready to become the next state to allow same-sex marriage — though they acknowledge it won't be easy, even with Democratic majorities in Springfield.

Voters in four states either supported gay marriage or opposed a ban on it on Election Day — a sweep that state Rep. Greg Harris, the prime sponsor of a bill introduced in the Illinois House, said represents 'a sea change' in public opinion. Those results, along with recent polling that shows support among an increasing number of Illinois voters, has Harris and other advocates counting votes and trying to determine not if legislation could get passed, but how soon.

The earliest anything could happen is during the veto session that starts next week or the waning days of the post-election lame duck session in early January. Or, supporters could wait until after the new session starts Jan. 9 — when Democrats will have supermajorities in the House and the Senate and a governor who has said he would sign the bill into law.

'We want to do it whenever we have the votes,' said Rick Garcia, director of the Equal Marriage Illinois Project. 'If we can do it in the veto session, we will. Otherwise we'll wait until spring.'

But the political realities in Springfield mean ending Illinois' 16-year-old law banning same-sex marriage isn't a slam dunk, in the next few weeks or next session.

Because gay rights are not strict party-line issues, a Democratic majority doesn't automatically mean the bill will pass. When the General Assembly approved civil unions for same-sex couples during the lame duck session in 2010, 17 Democrats — most from central and southern Illinois — voted no, while six Republicans said yes. The bill passed the House by just two votes and the Senate by just one, though Democrats had larger majorities in the House and Senate than they do now.

Lawmakers will have a slate of urgent issues competing for their time and political capital, from fixing the nation's worst pension shortfall to a major budget crisis. Legislative leaders will have to weigh how moving gay marriage to the floor will affect those issues, and when the timing might be best.

And as they did with civil unions, opponents will be actively fighting any effort to change the law.

The Catholic Conference of Illinois, which opposes same-sex civil unions or marriage, is distributing a toolkit to churches and schools that outlines the church's position that marriage between a man and a woman is what's best for society, and that anything else would undermine the sanctity of such unions.

In 2011, the organization created a new Defense of Marriage Department to lead the charge against changing state laws, and they are lobbying lawmakers.

'There obviously has been some kind of change (in public opinion). What it means and where it's going in Illinois is yet to be seen,' said Zach Wichmann, who heads the department. 'We have a position, and that isn't changing.'

Supporters say allowing gay marriage would provide practical benefits that same-sex couples don't get from civil unions, and that marriage is a much more commonly understood term than civil union. It's also a matter of principle.

'There should be one set of rules for everybody,' Garcia said.

Peter Breen is an attorney for the Thomas More Society, who is representing two downstate county clerks who are defending the state's gay marriage ban against a lawsuit filed by 25 gay couples. Breen believes same-sex marriage proponents are over-stating the significance of the Nov. 6 ballot measures, which he says were in left-leaning states — Maine, Maryland, Minnesota and Washington — and where gay rights advocates outspent opponents on political advertising.

'There is no great change as a nation on this issue,' he said.

Advocates hope to prove him wrong.

They note that President Barack Obama came out in support of gay marriage earlier this year — a position that didn't seem to hurt his re-election bid — and Chicago Mayor Rahm Emanuel recently said it should be one of the state's top legislative priorities.

In September, a poll for Southern Illinois University's Paul Simon Public Policy Institute found 44 percent of those polled said they believe gay and lesbian couples 'should be allowed to legally marry.' That's a 10-point increase from 2010, when only 34 percent backed gay marriage in a poll by the same institute.

On Election Day, voters in Lake County elected the state's fourth openly gay lawmaker, Democrat Sam Yingling, over Rep. Sandy Cole, R-Grayslake — who voted against the civil unions bill. And in exit polls conducted for the Associated Press a majority of voters in Illinois said the state should legally recognize same-sex marriages.

Add the four victories in other states, and Harris says the signs are undeniable.

'A lot of folks were saying, 'Wait to see how the election turns out,'' he said. 'Elections do matter, and they show trends, and they can't be ignored.'