Acclaimed actor Jim Broadbent (“Iris,” “Moulin Rouge”) has never traded on his looks. And he’s never looked less glamorous or been more inspiring than in tonight’s remarkable television movie “Longford” (7 p.m. today, HBO).

A balding, seemingly absentminded man with thick glasses and mottled complexion, the Earl of Longford (Broadbent) was an eccentric member of the House of Lords who put government and his family on the spot with his embrace of lost causes in the 1960s and 1970s.

A devout man who found faith as an adult, Longford spent hours visiting prisoners and providing them with books, advice and consolation. He scandalized the nation when he took up the cause of Myra Hindley (Samantha Morton), the convicted female half of a team of killers who kidnapped, abused and murdered children.

The movie does a rare and subtle job of letting viewers evaluate Longford’s mission and motivations. Was he brave to counsel the most hated and reviled woman in the nation? Or merely a naive do-gooder manipulated by a truly evil individual?

Based on a true story, this superior film also shows what happens to a politician who puts his faith in action and who defies a tabloid-driven culture that puts a premium on popular passions for vengeance.

Despite personal betrayal and grievous public rebuke, Longford never questioned his faith or his commitment to the spirit of redemption. A marvel to behold, Broadbent conveys this man’s quiet, smoldering resolve with remarkable restraint.

¢ A terror attack on a British airliner over Washington, D.C., exposes cracks in the alliance between the United States and the United Kingdom in the gripping miniseries “The State Within” (8 p.m. today and Sunday, BBC America, concludes next Sunday). A complex conspiracy tale every bit as compelling as “24,” “State” has the edgy cinematic style of a big-screen thriller and blends a capable British and American cast in surprising ways. Look for Sharon Gless (“Cagney and Lacey”) as a steely American secretary of defense at the heart of the intrigue.

¢ The Emmy-winning “Amazing Race” (7 p.m. Sunday, CBS) returns for a new season featuring 11 returning “All Star” teams.

¢ Viewers in search of the bloody, kill-or-be-killed school of television are in luck. “Raptor Force” on “Nature” (7 p.m., PBS, Sunday) looks at what aviation designers have learned from eagles, hawks and other flying predators. Liev Schreiber narrates.

Tonight’s highlights

¢ Scheduled on “Dateline” (7 p.m., NBC): Two brothers die under separate but similarly strange circumstances.

¢ Soledad O’Brien hosts a “Special Investigations Unit” (7 p.m., CNN) that looks at the life and oratory of Dr. Martin Luther King Jr.

¢ Justin Timberlake hosts “Saturday Night Live” (10:30 p.m., NBC).

Sunday’s highlights

¢ Cars festooned with corporate logos compete in the Daytona 500 (1 p.m., Fox).

¢ Scheduled on “60 Minutes” (6 p.m., CBS): Kurdistan; autism; Kenny Chesney.

¢ Andy dabbles in a make-a-wish charity on the season finale of “Extras” (9 p.m., HBO).