After trailing NBC among broadcast nets for the first two nights of the Republican National Convention, ABC leapfrogged into the top spot for Thursday’s final night, according to preliminary nationals from Nielsen.

Pending timezone adjustments later today, ABC’s coverage in the 10 p.m. Eastern hour drew a 1.0 rating and 3 share among viewers 18-49, even with CBS but ahead in total viewers, 4.2 million to 3.5 million. NBC (0.8/2, 3.3 million) was third in the demo, fourth if you include Univision (0.9/3, 2.3 million).

All three broadcast networks have been trailing Fox News, which averaged more 7 million viewers over the first two nights.

Top-ranked among non-political programs on the broadcast nets Thursday were reruns of “Big Brother” (2.3/6, 6.5 million), “The Big Bang Theory” (2.1/7, 7.8 million) and “Two and a Half Men” (1.9/6, 6.7 million), propelling CBS to a victory on the night in the demo and in total viewers.

ABC settled for second place thanks to firstrun episodes “Wipeout” (1.6/5, 5.8 million) and “Rookie Blue” (1.5/4, 5.8 million). Fox edged NBC for the bronze with “Raising Hope” (1.1/4, 3.3 million), “New Girl” (1.2/4, 3.4 million) and “Glee” (1.1/3, 3.6 million).

NBC aired repeats of “The Office” (1.1/4, 3.8 million), “Parks and Recreation” (1.0/3, 3.1 million) and a new “Saving Hope” (1.1/3, 4.1 million), while the CW offered “The Vampire Diaries” (0.5/1, 1.3 million) and “The Next” (0.5/1, 1.3 million). The CW fare was preempted in Los Angeles by an NFL Raiders-Seahawks exhibition game.

Preliminary 18-49 averages for the night: CBS 1.8/5, ABC 1.4/4, Univision 1.2/4, Fox 1.1/3, NBC 1.0/3, CW 0.5/1.

In total viewers: CBS 5.7 million, ABC 5.3 million, NBC 3.6 million, Fox 3.5 million, Univision 2.9 million, CW 1.3 million.