Co-sponsored by Philadelphia's ABC station, WPVI-TV, the 90-minute debate will take place Wednesday, April 16 at 8 p.m. from the National Constitution Center in Philadelphia.
The debate comes in the run-up to the April 22 Pennsylvania primary as Sen. Hillary Clinton (D-N.Y.) is attempting to close the gap with Sen. Barack Obama (D-Ill.), who is ahead in the delegate count and in the popular vote.
The polls give Clinton an edge in Pennsylvania, as Obama has been contending with fallout from his relationship with his divisive Chicago pastor, the Rev. Jeremiah Wright -- an issue he addressed in a groundbreaking speech Tuesday in Philadelphia.
This will be the 21st debate of the 2008 campaign. ABC News holds the record for the highest-rated debate of the record-breaking 2008 campaign, with 9.36 million viewers tuning in to the Democratic portion of back-to-back primetime debates in January days before the New Hampshire primary.
CBS News is still finalizing plans for a debate in North Carolina prior to the May 6 primary there and in Indiana, where 218 delegates are up for grabs. The debate would be a first this season for the network and for proposed moderator Katie Couric.