Democratic Debate on CNN Draws Record 15.3 Million Viewers

Donald Trump may have been the driving factor in record ratings numbers for the first two Republican primary debates of this election cycle, but he appears to have had a halo effect on the Democrats' first gathering as well.

In preliminary estimates from Nielsen, Tuesday's debate on CNN drew a big 15.3 million viewers -- the largest-ever crowd for a Democratic debate. Prior to last night, the highest-rated Democratic presidential primary debate on cable was CNN's 2008 Los Angeles debate, which averaged 8.3 million viewers. On broadcast, the highest-rated was ABC's 20008 Philadelphia debate, which drew 10.7 million viewers.

The Democratic debate was easily Tuesday night's most popular series or special on Twitter, according to Nielsen Social. Roughly 8.9 million people in the U.S. saw one or more of 2.8 million tweets sent about the debate, with the biggest moment coming at 9:50 p.m. ET, when 33,500 tweets were sent following Bernie Sanders' comment about Hilary Clinton's emails.