The Obama-McCain debate on Sept. 26 was watched by 52.4 million viewers, while more than 70 million saw Sen. Biden and Gov. Palin's sole meeting on Oct. 2. It's the second most-watched political debate ever, behind the 80.6 million people who watched the 1980 Carter-Reagan debate.
Nielsen tallied viewership for Wednesday's debate on ABC, CBS, Fox, NBC, Telemundo, Univision, BBC-America, CNBC, CNN, Fox News Channel and MSNBC.
The candidates' third and last debate is scheduled for Oct. 15 at Hofstra University in Hempsted, N.Y.