TONIGHT'S MUST-SEE

"The Shield," 7 p.m., FX. There's a thin line between intensity and obsession. Two men have crossed it, with a collision tonight. On one side is Lt. Vic Mackey, obsessed with his mistaken belief that Guardo, the gang leader, killed his friend Lem. On the other is Lt. Jon Kavanaugh. Obsessed with nailing Mackey for corruption, he planted evidence and told a witness to lie. Kavanaugh has a warrant out for Mackey's arrest. Mackey ignores it, heading alone into Guardo's turf. The story peaks as two great actors, Michael Chiklis and Forest Whitaker, collide.

"American Idol," 7 p.m., Fox. Many of the contestants have thrived when doing classic songs that have simple melodies. They've struggled when tackling the intricacies of modern music. They soared during British invasion and Tony Bennett weeks, wobbled in Gwen Stefani week. This could be a tough one, as the final eight work with Jennifer Lopez.

OF NOTE

"Rebel Without a Cause" (1955), 5 and 7:30 p.m., AMC. Here's a true classic, with three great young actors providing a simmering look at unrest. James Dean, Sal Mineo and Natalie Wood are superb.

"George Lopez," 7 p.m., ABC. George thinks it would build character if his spoiled niece Veronica (Aimee Garcia) worked in the factory. Alas, she finds that pretty people can get special privileges.

"According to Jim," 7:30 p.m., ABC. There's a fuss when Jim's wife and her sister show up on a "Chicks Gone Wild" tape.

"Nova: Sinking the Supership," 8 p.m., PBS. As World War II grew, the Japanese were building the Yamato, the world's biggest war ship. American pilots considered it an easy target and quickly sank it. This rerun looks at the effort.

"House," 8 p.m., Fox. Here's a change-of-pace for this excellent series: House and Cuddy are returning from a Singapore symposium when a plane passenger gets severely sick. Soon others (including Cuddy) are stricken; House needs a quick solution.

"Dancing With the Stars," 8 p.m., ABC. It's time to see the third person ousted, after Paulina Porizkova and Shandi Finnessey.

"Boston Legal," 9 p.m., ABC. The office is in consternation about the Brad-Denise romance and about Clarence and Claire.