If you have a niche: scratch it! The ABC Family Channel has done a nice job of defining itself as the place for teen and ‘tween melodramas. “The Secret Life of the American Teenager” (7 p.m., ABC Family) returns for a second season, even if our teen’s secret has long been exposed.

“Make it or Break It” (8 p.m., ABC Family) follows. A Cinderella tale set in the competitive world of Olympics-level gymnastics, “Break” stars Chelsea Hobbs as Emily, the poor scholarship girl given a chance to practice at a top gym in Colorado. Her arrival, and her instantly recognizable skills, threaten a trio of competitors, who serve as evil stepsisters to her scullery maid.

But these up-talking snoots have problems of their own, mostly in the form of their flighty and dysfunctional parents who provide more suds to this high-strung soap opera. Look for Peri Gilpin (“Frasier”) as one of the more sane gym mothers. She’s more Mama than drama here, but it’s nice to see her back on prime-time television.

• In a medium where the most profound issues are given sound-bite coverage, it’s nice to see a two-hour documentary devoted to “Iran and the West” (8 p.m., National Geographic).

Starting in 1978, “Iran” ticks off the highs and lows of a relationship marked by wars and proxy wars, multiple hostage crises and assassinations. It does a good job of cataloging Iran’s beef against the West, most notably America’s support of Iraq in its eight-year war with Iran and our role in sheltering Saddam Hussein from U.N. sanctions after he used weapons of mass destruction against Iran’s army.

It also concentrates on those times when U.S. and Iranian interests converged, most notably in 2001 when the Iranians assisted the U.S. military in attacking the Taliban in Afghanistan. The Bush administration would soon reward Tehran for this gesture by lumping it into the so-called “Axis of Evil.”

“Iran” presents interviews with former presidents and presidential advisers, Russian leader Vladimir Putin and former British Foreign Secretary Jack Straw.

For all of its resources, the film has some curious omissions. There is very little discussion of the influence that Iran exerts on the American-backed al-Maliki government in Iraq. Nor is much mention made of Iran’s long and complex dealings with Israel.

Still, “Iran” offers an interesting primer on a relationship between double dealers that is as complex as “The Godfather” or “The Godfather Part II.”

• On a related note, “The Daily Show with Jon Stewart” (10 p.m., Comedy Central) will spend the following week presenting interviews with Iranians protesting the recent Iranian election and apparent voter fraud.

Tonight’s other highlights

• A pain patient feels pushed to the limit on “House” (7 p.m., Fox).

• An assault on a military base poses a question on “Lie to Me” (8 p.m., Fox).

• A disturbed man believes he’s in love with Joan of Arc in the documentary “Invisible Girlfriend” (8 p.m., Documentary Channel).

• Scheduled on “History Detectives” (8 p.m., PBS, check local listings): Pancho Villa.

• Icy nonconversations abound on “Jon & Kate Plus 8” (8 p.m., TLC).

• Gabriel stumbles on “The Closer” (8 p.m., TNT).

• A practical joke ignites a rift on “CSI: Miami” (9 p.m., CBS).

• “Dateline” (9 p.m., NBC): murder in the garage.

Cult choice

A lawyer (Gary Oldman) discovers that his manipulative client (Kevin Bacon) may be a killer in the 1988 drama “Criminal Law” (8:35 p.m., IFC).