With its smart combination of power politics and emotional intrigue, “Commander in Chief” (8 p.m., ABC) has emerged as one of the new season’s few bona fide hits. Two new characters are introduced on tonight’s “Commander.”

Mark-Paul Gosselaar joins the cast as Richard McDonald, a savvy media consultant brought aboard to stem the administration’s loss of credibility and boost sagging poll numbers. Gosselaar co-starred on “NYPD Blue” for four seasons, which is interesting to note given that Steven Bochco, producer of “Blue,” was recently brought in to helm “Commander.”

Polly Bergen also will join the cast in the recurring role of the president’s mother, Kate Allen. This bit of casting acknowledges Bergen’s role in the 1964 big-screen comedy “Kisses For My President,” in which she played the first woman U.S. president.

¢ Now that we’ve got nearly 11 months under our belt, Barbara Walters can declare “The 10 Most Fascinating People of 2005” (9 p.m., ABC). Whenever Walters plays host to these annual chats, I’m reminded of one of my favorite Bugs Bunny cartoons. In it, a hairy ogre chases Bugs through a haunted castle. All of a sudden, Bugs transforms himself into a female manicurist, grabs the ogre’s hand and starts filing his fingernails, saying, “You monsters must lead such in-teresting lives and meet such in-teresting people!” Who knew Bugs was predicting the future of shallow American celebrity journalism.

This year, Walters rounds up the usual suspects, including Tom Cruise, Kanye West, Dakota Fanning, Thomas Mesereau (Michael Jackson’s lawyer), Lance Armstrong, Beth Holloway Twitty (the mother of the teen missing in Aruba), Teri Hatcher, Jamie Foxx and Condoleezza Rice. Walters will reveal the year’s most “fascinating” person at the program’s end. For those keeping score, this list contains not one doctor, scientist, entrepreneur, inventor, clergyman, author, philosopher or educator.

Other highlights

¢ Caroline Rhea is host to the two-hour finale of “The Biggest Loser” (8 p.m., NBC).

¢ A fight with an old mentor; a corpse in the fridge on “Bones” (8 p.m., Fox).

¢ Furious finger-pointing on “House” (9 p.m., Fox).

¢ A prison move involves risk of wider infection on “Threshold” (10 p.m., CBS).