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From W. NYC in New York, this is NPR's On the Media.

Brooke Ladstone is off this week. I'm Bob Carfield.

And I'm Beth Fertig. It's been almost four years since we first heard the name Valerie Plame.

The infamous outing of the CIA operative in a syndicated column by Robert Novak back in 2003

has spawned an investigation, a grand jury, and now, at long last, a trial. But it's not exactly a

who-done-it. In 2005, Cheney insider I. Lewis Libby revealed

himself as the source for then New York Times reporter Judith Miller. Libby is now being

tried for perjury and obstruction of justice in a case that, if the jury selection is

any indication, is more about memory and media than the identity of an undercover agent.

Chief Political correspondent for Slate magazine, John Dickerson, has been following the proceedings so far, and he joins us now.

John, welcome to On the Media.

Thanks for having me.

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