The 55 million watching the comparatively civil event in Nashville marked a considerable decline from the first debate between the two last month, when more than 73 million tuned in.
Fox News led all broadcast and cable networks with 14.7 million viewers, according to Nielsen.
ABC finished second with 10.8 million total viewers, followed by NBC with 10.2 million. CNN was fourth with 7.2 million viewers, followed by MSNBC’s 6.7 million and CBS’s 5.5 million.
In the 25- to 54-year-old demographic sought by advertisers, Fox News delivered 4.2 million viewers, followed by NBC with 3.9 million. ABC was fourth with 3.85 million, followed by CNN’s 2.85 million and MSNBC’s 1.5 million.