The second straight Democratic primary debate on a Saturday night drew lower ratings than the one in November, averaging a 1.1 for ABC. That was still good enough to tie CBS for the No. 1 spot in adults 18-49 for the night, pending updates. CBS may adjust down some as it had NFL pre-emptions in two large markets.
(6.71 million viewers before adjustment)
tvbythenumbers.zap2it.com

For comparison—Last Republican debate (Tues 12/15):

The fifth debate of the Republican presidential primary drew another big audience, giving CNN a big win for the day Tuesday. The debate drew 18.17 million viewers and a 3.8 rating in adults 18-49, better than the previous two on Fox Business and CNBC but behind the first two candidate face-offs on Fox News and CNN.

tvbythenumbers.zap2it.com

Smart move, Dems. Pick the Saturday before Christmas so you can have 1/3 the number of views on a Network show as the GOP had on cable.

The only positive spin I can think of is that the more people see the Klown Kar in action, the more ridiculous they look. If only.