A lack of buzz, no on-air presence for three months and an overall slumping performance of late for the network conspired to bring down numbers for ABC’s returning TGIT dramas last night. The Alphabet did earn a tie with Fox’s “American Idol” for the night’s lead in young adults, thanks largely to a still-potent “Grey’s Anatomy,” but “Scandal” and “How to Get Away With Murder” sagged from their fall numbers and were significantly cooler than a year ago.

The competition seemed largely unfazed by the return of ABC’s femme-friendly dramas, with most shows on par or within a tenth of their week-ago averages. CBS’ “The Big Bang Theory,” the night’s No. 1 show, appears to be up from last week, while recent NBC drama addition “Shades of Blue” held steady.

Thursday’s entertainment programs faced competition from the latest presidential primary debate, this one on the Democratic side. In Nielsen’s metered-market overnights, it averaged a combined 6.3 rating on PBS (3.3) and CNN (3.0), which sublicensed the event from the pubcaster. When total-viewer numbers come in later this morning, the debate is expected to draw in the vicinity of 9 million to 10 million.

Looking at Thursday’s entertainment action, ABC opened the night with “Grey’s Anatomy” (2.4 rating/8 share in adults 18-49, 8.2 million viewers overall), which was at its fall average and within a tenth of its fall finale; the medical drama won its hour in adults 18-34 (1.9/9) and all female demos. “Scandal” (2.1/7 in 18-49, 6.9 million viewers overall) was at an outright season low and down 12% from its fall finale, while “How to Get Away With Murder” (1.8/6 in 18-49, 5.8 million viewers) matched its lowest score to date and was 22% below its fall finale. Overall, this year’s winter premieres of “TGIT” were down a combined 34% in 18-49 vs. last year (2.1 vs. 3.2).

Despite the declines, the Thursday dramas did provide ABC with its highest-rated night of entertainment programming since the lineup’s fall finales 12 weeks ago (Nov. 19). And ABC figures to win the night outright in L+3 thanks to the show’s large lifts in delayed viewing.

CBS as usual claimed Thursday’s top program in “The Big Bang Theory” (3.8/14 in 18-49, 16.0 million viewers overall), which is poised for slight week over week gains in the finals if it’s revised up to a 3.9 as expected. It was followed by “Life in Pieces” (2.1/7 in 18-49, 9.5 million viewers overall), which was down a tick from its best-since-premiere performance of last week, and a steady “Mom” (1.7/6 in 18-49, 8.1 million viewers overall). A special repeat of “The Big Bang Theory” (1.4/5 in 18-49, 6.4 million viewers overall) matched last week’s “Angel From Hell” original, and “Elementary” (1.1/4 in 18-49, 6.1 million viewers overall) equaled last week’s rating.

At NBC, “You, Me and the Apocalypse” (0.8/3 in 18-49, 3.0 million viewers overall) and “The Blacklist” (1.4/4 in 18-49, 6.3 million viewers overall) were down a tenth from last week, but “Shades of Blue” (1.1/4 in 18-49, 5.4 million viewers overall) was able to hold steady despite the arrival of “How to Get Away With Murder.” The Jennifer Lopez cop drama, which has been renewed for a second season, continues to be a big gainer in delayed viewing; last week it posted the largest percentage increases from “live plus same-day” to “live plus-3” among any series on the Big Four broadcast networks — up 76% in 18-49 rating (1.15 to 2.02) and 60% in total viewers (5.64 million to 9.03 million).

Fox’s two-hour “American Idol” (2.1/7 in 18-49, 8.9 million viewers overall) was down a tenth from last week. It peaked in the 8:30 p.m. half-hour, where it edged ahead of CBS’ “Life in Pieces” in 18-49.

And CW’s “DC’s Legends of Tomorrow” (0.9/3 in 18-49, 2.4 million viewers overall) held steady in its fourth week, edging out NBC for the hour in 18-49. “The 100” (0.5/2 in 18-49, 1.3 million viewers overall) was down a tenth from last week’s second episode of the season.