Democratic presidential hopefuls Minnesota Senator Amy Klobuchar (L) and Mayor of South Bend, Indiana, Pete Buttigieg (R) participate in the fifth Democratic primary debate of the 2020 presidential campaign season co-hosted by MSNBC and The Washington Post at Tyler Perry Studios in Atlanta, Georgia on November 20, 2019. (Photo by SAUL LOEB / AFP) (Photo by SAUL LOEB/AFP via Getty Images)
Democratic presidential hopefuls Minnesota Senator Amy Klobuchar (L) and Mayor of South Bend, Indiana, Pete Buttigieg (R) participate in the fifth Democratic primary debate of the 2020 presidential campaign season co-hosted by MSNBC and The Washington Post at Tyler Perry Studios in Atlanta, Georgia on November 20, 2019. (Photo by SAUL LOEB / AFP) (Photo by SAUL LOEB/AFP via Getty Images)
PHOTO: Saul Loeb/AFP/Getty Images
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(CNN Business) —  

Wednesday’s Democratic debate, the fifth this year, was the least-watched debate of this election cycle. The ratings for MSNBC were down more than 20% from last month’s match-up on CNN.

One obvious reason: The televised impeachment hearings earlier in the day sucked all the political oxygen out of the room. Some viewers who spent all day watching House testimony probably didn’t want to spend all night watching a debate.

On the other hand, cable news viewership levels have been significantly elevated by the hearings, so that theoretically could have benefited MSNBC. But it didn’t.

About 6.6 million people were watching between 9 p.m. and 11:15 p.m. ET, according to overnight Nielsen ratings.

The debate was also live-streamed by MSNBC’s partner, The Washington Post, and by several NBC-affiliated websites.

MSNBC said that the debate “generated more than 1.3 million live video streams” across its sites, but those are just live-stream starts, which are not comparable to TV ratings.

Nielsen measures the per-minute average audience for shows, while live-stream starts signifies how many times a video begins playing, even if the user only watches for a few seconds or minutes.

The most-watched Democratic debate of the season was the very first, back in June, both because of the novelty factor and because it was carried live on NBC, MSNBC and Telemundo. The second night of that two-part debate averaged 18.1 million viewers across the three networks.

Ratings for subsequent debates have declined over time, which network executives generally expected, to varying degrees.

CNN’s October debate, co-sponsored by The New York Times, averaged 8.5 million viewers.

The next Democratic face-off will be held on December 19 in Los Angeles. PBS “NewsHour” and Politico are co-sponsoring the debate, and CNN is also airing it live.