ABC news show is down 15 percent in 18-49s The post-Ted Koppel “Nightline” has faced questions about its viability since its debut two months ago, but those questions are hardly new. Koppel faced them for much of the time he anchored the show. What is new is a hefty decline in ratings. Will ABC continue to stand behind the late-night news show, and for how long? The question would seem to gain urgency with the network's improved primetime ratings, making a makever of the 11:30 p.m. timeslot all that more attractive. For the week ended Jan. 15, “Nightline” averaged 3.6...
