"This issue is not just about two adults and their emotional relational and financial commitment to another," said Rep. Tom Morrison, a Palatine Republican. "Redefining marriage has far reaching implications in our society."
The measure cleared the Senate on Valentine's Day with the support of 33 Democrats and a single Republican. Backers had expressed confidence that the bill would be approved by the House in mid-March. But it took the supporters months to secure enough yes votes to win the House's approval.
In September, Minneapolis Mayor R.T. Rybak even went to Chicago to encourage gay couples to hold their nuptials in his city if they were tired of waiting for Illinois lawmakers to act.
Although Illinois once appeared poised to become the first Midwestern state to approve gay marriage in the Legislature, Minnesota did it sooner and started holding its first same-sex weddings over the summer. Iowa allows gay marriages too because of a court ruling, not a legislative vote.
The issue caused internal conflict among Illinois Republicans as the party works to balance efforts to appeal more to younger voters, minorities and women with the more socially conservative positions of some party members.
For months, the leaders of several black mega-churches lobbied the districts of black House members with an aggressive robocall campaign against gay marriage, placing an uncomfortable spotlight on the mostly Democratic black caucus. Many remained undecided until the vote neared.
Illinois approved civil unions in 2011.