Fast National ratings for Tuesday, August 28, 2012.
 
"America's Got Talent" dominated the first two hours of primetime and helped NBC dominate Tuesday overall, but as the only network whose official primetime ratings weren't hampered by low-rated coverage of the Republican National Convention, FOX won an asterisked victory among young viewers.
 
Note that because of political coverage, which aired live throughout the country, Tuesday's overall ratings are extra imprecise.
 
Among adults 18-49, FOX won Tuesday night with a 2.1 rating, nipping the 2.0 rating for NBC in the key demographic. [Of course, NBC won the two hours that the two networks went head-to-head.] CBS averaged a 1.0 key demo rating, beating the 0.6 rating for ABC and The CW's 0.2 rating.
 
Overall, though, NBC averaged an estimated 8.15 million viewers to go with a 4.9 rating/8 share for Tuesday primetime, easily beating the 4.1/7 and 6.23 million viewers for CBS. FOX was third with a 2.9/5 and 5.01 million viewers, which nearly doubled the 1.8/3 and 2.535 million viewers for ABC. The CW averaged a 0.4/1 and 650,000 viewers for the night.
 
8 p.m. - NBC started the night in first with 8.98 million viewers and a 2.2 rating among adults 18-49 for "America's Got Talent." CBS' repeat of "NCIS" was second overall with 8.19 million viewers and third in the key demo with a 1.2 rating. FOX's repeat of "MasterChef" was second in the key demo with a 1.5 rating and a distant third overall with 3.51 million viewers. ABC's repeats of "The Middle" and "Last Man Standing" averaged 3.24 million viewers and a 0.8 key demo rating for fourth. On The CW, a repeat of "Hart of Dixie" averaged 735,000 viewers and a 0.2 key demo rating.
 
9 p.m. - "America's Got Talent" remained in first overall in the 9 p.m. hour with 10.09 million viewers, but NBC dropped to second among adults 18-49 with a 2.6 rating. CBS' "NCIS: Los Angeles" was second overall with 7.17 million viewers and was third with a 1.1 key demo rating. A new "MasterChef" won the hour with a 2.8 key demo rating and was third with 6.5 million viewers, comfortably up from last week. ABC's repeats of "Happy Endings" and "Don't Trust the B---- in Apartment 23" averaged 2.025 million viewers and a 0.6 key demo rating, beating the 566,000 viewers and 0.2 key demo rating for The CW's "The Next" encore.
 
10 p.m. - NBC's Republican Convention coverage won the 10 p.m. hour with 5.39 million viewers and a 1.3 key demo rating. CBS' coverage averaged 3.32 million viewers and a 0.6 key demo rating, compared to the 2.34 million viewers and 0.5 key demo rating for ABC's coverage.
 
All ratings information comes from preliminary Fast National Nielsen data, which includes live and same-day DVR viewing. All numbers are subject to change, particularly in the case of live events.