On a special two-part episode of “My Name is Earl” (7 p.m., NBC), Earl and Randy go on a mission to save Catalina (Nadine Velazquez) from deportation and find themselves in some hot water south of the border. John Leguizamo guest stars in the second half hour.

One of the more startling things about “Earl” and its relative success is its darkly comic treatment of Catalina’s plight. She’s smart and gorgeous but works two fairly grim jobs, scouring toilets at Earl’s squalid motel court and working as an exotic dancer at Club Chubby.

Catalina is not in this country for its economic opportunities. She was brutalized in her homeland. In the show’s over-the-top fashion, she rattles off tales of torture, assassination, execution and dismemberment. This is absurd, of course. It also provides Catalina with an alluring mystery. She’s aware of a world that her American cohorts can perceive only dimly.

“Earl” is hardly the only prime time show to deal with immigration. On tonight’s “Smallville” (7 p.m., CW), Clark learns that a neighbor is holding migrant workers captive. The Super Boy also asks his mother (Annette O’Toole) to help him keep two young neighbors from being deported. Their plight reminds Clark of his own status as an illegal alien from another planet.

And ABC airs the pilot of “Ugly Betty” (7 p.m., ABC), starring America Ferrera as Betty Suarez. As fans of “Betty” have already learned, our heroine is in for a shock when, in a later episode, she discovers that her father (Tony Plana) is an illegal alien and has been using a fake social security number.

So we have three shows – two comedies and a fantasy – all airing at the very same hour of television’s most competitive evening, presenting three different takes on the immigration question.

This network approach stands in contrast to cable-news shows in which the subject is treated in ominous tones. On a recent episode of “Glenn Beck” (8 p.m., CNN Headline News), the former DJ declared, “The situation with our borders is part of the Perfect Storm that’s forming against us.” In all fairness, Beck likes to conflate almost every situation into a Perfect Storm of fear.

Beck is not alone. CNN’s Lou Dobbs sees illegal immigration as part of an overall “war” on middle-class America. And, of course, Bill O’Reilly, the Arch Druid of Perpetual Outrage, has plenty to say about the subject.

What explains the difference between the network and cable approach? On a very basic level, one is popular and one is not. Networks have to appeal to a broader audience and, more to the point, attract younger viewers and the advertisers that chase them. “Betty” and “Earl” have done quite well in capturing younger viewers.

The audience for cable “news” shouting shows tends to skew much older and reflect a crankier worldview. Fed a steady diet of Dobbs/Beck/O’Reilly, you would believe that the world went to Hades in a handbasket some decades back.

Tonight’s other highlights

¢ A killer leaves tiny facsimiles behind on “CSI” (8 p.m., CBS). Danny Bonaduce guest stars.

¢ A socialite stands accused of killing his mistress on “Shark” (9 p.m., CBS).

¢ A figure from Jack’s past returns on “Men in Trees” (9 p.m., ABC).