Thousands of gay marriage supporters have descended upon the state Capitol for what they're calling a "March on Springfield."
Gov. Pat Quinn and U.S. Sen. Dick Durbin launched the campaign's noon concert on Tuesday. A rally and march will follow.
Lawmakers are back in Springfield for the fall veto session and legislation allowing same-sex couples to marry could come up.
Earlier in the year a bill passed the state Senate but stalled in the House. House Speaker Michael Madigan has said about a dozen votes are still needed but gay marriage activist Rick Garcia says significant progress has been made. Sixty votes are needed for passage in the House.
Quinn says he'll sign the legislation if it's approved.
Illinois allows civil unions. More than a dozen states allow gay marriage.
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