The Democratic Party Platform (see our post about that) cut out language from earlier platforms referring to “God.” Paul Ryan and other Republicans jumped on that omission, so party leaders introduced an amendment putting “God” back in.
But the convention chairman, Los Angeles Mayor Antonio Villaraigosa, had to call for three voice votes from the floor. It appeared that most of the convention voted “nay.” Nevertheless, the chairman gavelled it through, ruling that the “ayes” had it and that “God” would be put back into the party platform. Whereupon the floor erupted in boos.
Also put back in was language affirming Jerusalem as the capital of Israel.
See this for details and a video. Also Democratic National Convention 2012 platform altered to add God | World | News | National Post.