Stephen joins Occupy Wall Street, Wisconsin allows concealed weapons in its Capitol, and Neil MacGregor tells the history of the world with 100 objects.

Newt Gingrich denies lobbying, conservatives bid Barney Frank farewell, and Stephen Sondheim ponders the artist life.

Jon Stewart adopts the Colbert Super PAC, Stephen makes a monumental announcement, and Mike Allen anticipates Stephen's possible South Carolina results.

Barack Obama delivers his State of the Union address, Maurice Sendak gives Stephen a storybook ending, and Terry Gross provides a fresh perspective on Bill O'Reilly.

Herman Cain discusses the Chinese nuclear threat, the government releases information on Muffingate, and Michael Pollan talks food.

Herman Cain's campaign ad gets buzz, Ben & Jerry's endorses Occupy Wall Street, and Susan Saladoff explores the myth of frivolous lawsuits.

PETA files a lawsuit to free captive whales, immigrant farm workers flee Alabama, and Taylor Branch discusses the multi-billion dollar college sports industry.

Hans Beinholtz hawks Europe to investors, Colbert Super PAC adopts Herman Cain's fundraising strategy, and Nathan Wolfe examines viral pandemics.

Stephen sets the date for his GOP debate, Dick Harpootlian helps Colbert Super PAC with its referendum, and ballet dancer David Hallberg performs.

Sarah Palin bows out of the presidential race, Stephen apologizes to Karl Rove, and Lieutenant Colonel Jason Amerine discusses the early days of the Afghanistan War.

The Occupy Wall Street movement goes global, Stephen unveils Colbert Super PAC's NBA lockout ad, and Harry Belafonte talks political activism.

Donald Trump backs out of his debate, Madison charges protesters for the right to protest, and Mark Whitaker pays tribute to his parents with his memoir.

Rick Perry drops out of the GOP race, Newt Gingrich's ex-wife exposes his controversial marital request, and Carrie Rebora Barratt discusses historical American art.

Stephen unveils Colbert Super PAC's message, Frank Luntz conducts a focus group, and GOP presidential candidate Jon Huntsman talks about fixing America.

Occupy Wall Street wears out its welcome, Stephen unveils his second NBA lockout Super PAC ad, and Toby Keith performs.

Herman Cain's sexual harassment controversy unfolds; Stephen returns to Wall Street; and Yo-Yo Ma, Stuart Duncan, Edgar Meyer and Chris Thile perform.

Herman Cain blames Democrats for his troubles, Michigan Senate Republicans amend an anti-bullying bill, and Father James Martin explores the role of comedy in religion.

Rick Perry puts out a controversial ad, doctors perform fecal transplants, and Jack Abramoff exposes the truth about Washington corruption.

Rick Santorum rises in the polls, Stephen remembers the late Kim Jong-il, and Bernie Sanders strives to overturn the Citizens United decision.

Rick Davis weighs in on Chris Christie fever, ESPN pulls Hank Williams Jr.'s song, and John Lithgow talks drama.

Herman Cain may or may not be joking about an electrified border fence, schools take potatoes off their menus, and Steven Pinker discusses the decline of human violence.

Make Us Great Again airs its Rick Perry ad, Colbert Super PAC takes on issue advocacy, and Niall Ferguson discusses the end of western dominance.

Herman Cain abandons his campaign, William Tapley studies apocalyptic signs, and Jimmie Johnson reveals NASCAR racing details.

Newt Gingrich alerts America to electromagnetic threats, Norway faces a butter crisis, and Samuel L. Jackson considers Martin Luther King Jr.'s personal life.

Mitt Romney faces questions about his tax rate, Stephen announces his South Carolina rally, and David Frum shares his hopes for the Republican Party.