One young Marine, in a downward spiral, keeps his torment and pain bottled up after returning home from Iraq.

The military teaches soldiers how to fight, how to kill, how to survive. But who teaches them how to live with themselves? Examining an underreported story of the Iraq war: the psychological cost of those who fight it.

A look at two contrasting images: one of empty Ohio storefronts, where local TV manufacturing plants have closed down; the other of a sea of high rises in the China boomtown of Shenzhen. The connection? Wal-Mart. Some credit Wal-Mart’s focus on low costs with helping contain U.S. inflation, but others say it drives production of American consumer goods overseas, resulting in problems here at home.

It’s more than simple buying and selling: these multibillion-dollar corporations shape today’s culture, media, who we are and how we look. In The Persuaders, FRONTLINE analyzes how big businesses advertise more than just a product -- they’re selling a lifestyle.

Did America rush into a war in Iraq for which is was unprepared? Could the volatility in Iraq have been prevented? FRONTLINE takes an in-depth, behind the scenes look at what some government officials said was the underlying cause of America’s problems in Iraq: prewar political infighting that hampered efforts to plan for an orderly postwar transition.

In this excerpt from the 2003 FRONTLINE documentary "Truth, War & Consequences," correspondent Martin Smith asks Ahmad Chalabi about the intelligence that led to the U.S. invasion of Iraq.

In this excerpt from the 2003 FRONTLINE documentary "Truth, War & Consequences," correspondent Martin Smith asks Ahmad Chalabi about the intelligence that led to the U.S. invasion of Iraq.

Footage of "The Man Who Knew" talking about the work of FBI agents, how he handles the emotional challenges of his job, and "ordered liberty" -- the delicate balancing of national security and civil liberties.

A lonely, precocious Army brat, "Newtie," as his mother called him, loved animals and the movies. At age 10, he presented a plan to build a zoo to the local mayor. But at age 15, his life is changed by a visit to the battle site of Verdun, where nearly 1 million died in World War I. At Verdun, Newt saw that it was politics that truly shaped the world.

In this investigative biography of the outspoken and controversial speaker, which first aired in 1996, correspondent Peter J. Boyer takes an inside look at how Gingrich led the GOP to become the majority party and examines the childhood, people and events that shaped his personality and political career.

In high school, Newt learns to play politics as an outsider. A Republican in overwhelmingly Democratic Georgia, he casts himself as Richard Nixon in a class play. He proposes an article predicting a coming Republican majority to "Harper's" Magazine. And he begins a furtive romance with his high school geometry teacher.

Newt seizes control of GOPAC, the Republican political action committee, and makes it an instrument for his conservative political vision. Piercing political language is his greatest weapon and GOPAC relentless promotes "Newtspeak." Newt records training tapes for candidates and teaches a history course based on his belief that the Great Society imperiled the very survival of American culture.

With his Contract With America, the center of domestic political power shifts to Newt's agenda. His House of Representatives passes nine of the contract's 10 commandments in its first 100 days. But the harsh glare of the spotlight shines on some of Newt's excesses, including a $4.5 million book advance, and disorder in his personal life.

Newt arrives in Congress with two dreams: becoming speaker of the House and building a Republican majority. He learns controversy is a way to attract attention and he seizes on new media, like C-Span, to attack the enemy and recruit his own political army. To defeat the Democrats, he believes Republicans must destroy their mindset as a complacent minority, willing to compromise.

In his first congressional campaign Newt runs as a liberal Republican reformer, endorsed by environmentalists. Negative ads by his opponent pierce Newt's thin skin, but by his third campaign he sheds his old politics and unveils a new strategy: "Raise hell. Raise hell all the time." He wins a seat that had been a Democratic stronghold for 25 years.

Security expert Bruce Schneier breaks down the NSA's Tailored Access Operations unit, and how it is able to install its own surveillance hardware on commercial computers and devices.

The complete WGBH footage of then-Harvard Law student Barack Obama speaking at a rally supporting Derrick Bell, the first black tenured professor at the school.

One day in 1968, Jane Elliott, a teacher in a small, all-white Iowa town, divided her third-grade class into blue-eyed and brown-eyed groups and gave them a daring lesson in discrimination. This is the story of that lesson, its lasting impact on the children, and its enduring power 30 years later.