Republican state lawmakers unveiled a fourth version today of a proposed constitutional marriage that would prohibit same-sex marriages and civil unions. 

Earlier versions of the bill raised concerns from opponents that it could invalidate domestic partner benefits offered by employers. The latest version, Senate Bill 514, specifically exempts contracts entered into by "private parties."  

It also makes a crucial change in the timing of the amendment's appearance before voters.  Earlier versions would have put the amendment on the ballot in November 2012, leading some critics to accuse the bill's backers of using it as a political issue to drive Republican voter turnout.   

The new version moves the ballot date to May, 2012, during primary elections. Democratic sources say the change has given the measure a few votes from conservative Democrats who were inclined to support it, anyway.

As of this morning, the Senate's version of the amendment was set to be heard in Senate Judiciary 1 committee and voted later on the Senate floor. But at 12:45, House leaders announced they, not the Senate, would move forward on a House version of the bill, with a floor vote later today in their chamber. The amendment changed chambers, bill numbers, content, ballot date, committees, and rooms, all within 75 minutes. 

In House Rules this afternoon, it was standing-room only. Most of those attending were wearing stickers in favor of the amendment, having just come from a rally amendment backers held today outside the building.  Many members of the public had come hoping to speak on both sides of the issue, but House Rules Chairman Tim Moore elected not to allow public comment on the measure.

The amendment passed the Rules committee after about 30 minutes of discussion.  House debate is expected to start around 2:45pm. Speaker Thom Tillis said earlier he would allow open floor debate on the proposal before its initial vote.

We're streaming the debate live at WRAL.com