Marriage-equality advocates had been hoping for another big win, just weeks before the Supreme Court is scheduled to announce its decisions in the two gay-rights cases argued earlier this year. Instead, they were badly disappointed, if not stunned. It had looked since the beginning of the year as though Illinois would be the next big state—the thirteenth, and the second most populous after New York—to adopt same-sex marriage. It was anticipated as a final reminder that the country was headed inexorably toward marriage equality, right before the Supreme Court’s landmark rulings, expected on or before June 27th.

But last Friday, proving that it is still extremely difficult to get a gay civil-rights bill through a legislative body, the Illinois House, controlled seventy-one to forty-seven by Democrats, adjourned without taking the expected vote on the marriage bill. The bill had previously passed the Democratic controlled Senate and was ready for the signature of the Democratic Governor Pat Quinn, who had lobbied for it, although apparently not hard enough for it to succeed.

Representative Greg Harris, the bill’s main sponsor, who is gay, announced at the last minute that he would not bring the legislation up for a floor vote, saying that he’d been asked by a number of his Democratic colleagues to delay it until the next session in order to give the legislators more time to discuss the bill with their constituents. “I apologize to the families who were hoping to wake up tomorrow as full and equal citizens of this state,” Harris said, barely holding back tears. He said he’d been promised a positive vote in November, when the House next reconvenes—but the legislation would then have to be passed again in the State Senate. The bill had already been delayed several times during the last five months in an effort to line up votes. Governor Quinn had indicated earlier that he believed the votes for the bill were there, but that whip count seemed to collapse in the waning moments of the legislative session.

Proponents of the bill reacted with shock, quickly followed by anger and some finger-pointing. Marc Solomon, the campaign director of the national-rights group Freedom to Marry, called the situation a “disgrace.” Jim Bennett, of Lambda Legal, which is suing in Illinois over same-sex marriage, called it “a stunning failure.” There has been a standing debate among advocates about whether, in cases like this, it is best to go ahead with a vote even if it is likely that it will fail: doing so has the advantage of putting lawmakers on the record, but it may give opponents a symbolic victory. In the end, Harris decided that a loss would be worse.

What happened? The bill had the endorsement of Illinois State House alumnus Barack Obama, who, during a visit two days before the vote, said, “Here in Illinois, we’ve got a vote on same-sex marriage that’s going to be coming up in the state legislature. And I just want to say for the record it’s something that I deeply support.” Almost every high-ranking elected official in Illinois, including Chicago Mayor Rahm Emanuel and U.S. Senators Dick Durbin, a Democrat, and Mark Kirk, who earlier this year became only the second sitting Republican Senator to support same-sex marriage. Even Bill Clinton talked up the Illinois legislation. It wasn’t enough.

The lack of a recorded vote makes it hard to say for sure who backed down. Comments from those involved varied widely as to who was to blame. Some advocates were quoted as saying that the bill failed because it lacked full support from the twenty-member Illinois House Legislative Black Caucus. While several of its members denied responsibility, public reports indicated that the bill had the support of just half of them at best. Others criticized Harris for not allowing a recorded vote. Harris blamed Governor Quinn, in part, for saying in advance that the bill had enough votes in favor for passage. Others complained that the effort lacked transparency and relied too much on private lobbyists retained by wealthy gay-rights donors. Still others blamed the House Democratic Speaker Mike Madigan for failing to deliver all of his members. He quietly moved on Friday night to extend the window for passage of the bill beyond the adjournment if a special legislative session is called, but it would still require a new concurrence in the Senate. Strangely, few of those speaking after the session blamed the bill’s main opponents in the Republican Party of Illinois and the Catholic Church, which had lobbied heavily and successfully in opposition to the bill.

All of this proves how difficult passing same-sex marriage legislation continues to be in many places, and how patience and determination have proven to be the only strategies to consistently deliver results for marriage advocates. Many states with same-sex marriage laws now in place, like New York, went through unsuccessful legislative efforts first. The situation in Illinois is the same one that New York faced: in 2009, the New York legislature rejected a bill; it finally passed in June of 2011. The failure in Illinois is a reminder of just how hard fought the New York moment was.

In Illinois, Representative Harris tried to be optimistic about the bill’s prospects when the legislature next convenes. “I have to keep my eye—as we all must—on the ultimate prize,” he said. “They have told me they will return in November and they have given me their word they will be prepared to support this legislation.”

But, by November, it will likely be a very different political landscape, one shaped by how the Justices decide the Supreme Court rulings due this month.

Richard Socarides is an attorney, political strategist, writer, and longtime gay-rights advocate. He served as White House Special Assistant and Senior Adviser during the Clinton Administration.