Update: The debate concluded around 9:30 p.m. ABC News provides an hour or so of post-debate analysis on the live stream (see below).
DENVER (AP) - The first debate between Democratic President Barack Obama and Republican nominee Mitt Romney is under way at the University of Denver.
Obama and Romney are taking the stage in the first of three 90-minute presidential debates scheduled this month.
The debate is expected to focus on domestic policy. The moderator is PBS newsman Jim Lehrer. He will open each 15-minute segment with a question, and then Obama and Romney will have two minutes apiece to answer.
After that, it's up to Lehrer to keep the conversation going and to intervene if one candidate speaks too long.
National polls show the two candidates in a tight race among likely voters. But Obama has the advantage in many of the battlegrounds, including Colorado.