The first mano a mano showdown between Democratic contenders Hillary Clinton and Barack Obama was the most-watched primary debate in cable news history.
CNN's Jan. 31 debate between Clinton and Obama attracted 8.3 million viewers, with 3.3 million of them in cable news' key demographic of 25-to-54-year olds. That easily beats the previous cable debate leader of 4.9 million viewers for CNN's Democratic face-off in South Carolina.
ABC News holds the debate ratings record for the season. More than 9 million viewers watched the network's primetime Democratic debate on Jan. 5—two days before the New Hampshire primary.