Commission members wanted a relaxed format that included time for unpredictable questioning and challenges between the two vice-presidential candidates. On Wednesday, the commission unanimously rejected a proposal sought by advisers to Ms. Palin and Senator John McCain of Arizona, the Republican presidential nominee, to have the moderator ask questions and the candidates answer, with no time for unfettered exchanges. Advisers to Mr. Biden say they were comfortable with either format.
The debate formats were negotiated by Senator Lindsey Graham, Republican of South Carolina, representing the McCain campaign, and Representative Rahm Emanuel, Democrat of Illinois, for the Obama camp. A handful of aides from both camps were also involved, hammering out issues between themselves and then holding conference calls with members of the commission to reach final agreements, people involved in the process said.