Barack Obama, Mitt Romney

President Barack Obama and Republican nominee Mitt Romney square off tonight in the first of three presidential debates leading up to the election on Nov. 6. (Vice President Joe Biden and Romney's running mate, Paul Ryan, will go head-to-head once, next Thursday.)

Tonight's debate at the University of Denver will focus on the topic of domestic policy and will be moderated by Jim Lehrer.

Candy Crowley will be first female presidential-debate moderator in 20 years

The 90-minute debate is scheduled to start at 9/8c and will be broadcast by all the major networks, as well as on C-SPAN, CNN, Fox News, MSNBC and other cable news channels. It will also be streamed online.

The debate will pre-empt several shows, including Modern Family on ABC, Criminal Minds and CSI: Crime Scene Investigation on CBS, and Law & Order: SVU on NBC, while Fox will air a truncated, one-hour episode of The X Factor at 8/7c. The CW will air the premiere of Supernatural at 9/8c as planned.