Democratic National Convention organizers on Tuesday announced additions to the speaking lineup for the first night of the presidential nominating event, adding to the rostrum Speaker Nancy Pelosi (Calif.), Sen. Claire McCaskill (Mo.) and Craig Robinson, brother of Michelle Obama. Michelle Obama will be the headliner for Monday’s prime-time speeches, which will follow the theme of “One Nation.” The Denver convention kicks off that day and concludes Thursday when Sen. Barack Obama (Ill.) formally accepts the Democratic nomination for president. Also Monday, Democrats will pay tribute to the ailing Sen. Edward Kennedy (Mass.), who is battling a brain tumor and is unlikely to travel to the convention. Kennedy recently taped a video message to be aired during the event.