Governor Martin O'Malley signs the same-sex marriage bill at the Statehouse. (Amy Davis/Baltimore Sun /March 1, 2012)
The Maryland Marriage Alliance, made up of mostly African-American church leaders, said in a news release they will take the lead role in gathering signatures to put the law on the November 2012 ballot. They will be joined by the Maryland Catholic Conference, and, they said, the National Organization for Marriage, a national group that supports traditional unions.
O'Malley is set to sign the bill at 5 p.m. Thursday, though it would not go into effect until January 2013.
Opponents must gather nearly 56,000 valid signatures by June 30 in order to trigger the referendum. Maryland's referendum process was rarely used until recently. Last year opponents of the Maryland Dream Act, legislation allowing in-state tuition discounts for illegal immigrants, was easily petitioned to the November 2012 ballot.

